fix: Improve face creation from edges using BRepOffsetAPI_MakeFilling

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

CMakeLists.txt

@@ -28,19 +28,10 @@ endif()
 message(STATUS "OpenCASCADE_INCLUDE_DIRS: ${OpenCASCADE_INCLUDE_DIRS}")
 message(STATUS "OpenCASCADE_LIBRARIES: ${OpenCASCADE_LIBRARIES}")
 
+file(GLOB SOURCES "src/*.cpp")
+
 add_executable(OpenCAD
-    src/main.cpp
-    src/MainWindow.cpp
-    src/ViewportWidget.cpp
-    src/ViewCube.cpp
-    src/SketchGrid.cpp
-    src/Document.cpp
-    src/Feature.cpp
-    src/SketchFeature.cpp
-    src/SketchLine.cpp
-    src/FeatureBrowser.cpp
-	src/ApplicationController.cpp
-	src/Camera.cpp
+    ${SOURCES}
     resources.qrc
 )
 

README.md

@@ -0,0 +1,19 @@
+# Unnamed CAD Software
+
+## Development
+
+### Building
+
+On Debian 12:
+
+```bash
+$ sudo apt install cmake qt6-base-dev qt6-svg-dev libtbb-dev
+$ sudo apt install libocct-foundation-dev libocct-modeling-data-dev libocct-modeling-algorithms-dev libocct-visualization-dev
+
+$ mkdir build
+$ cd build/
+$ cmake ..
+$ make
+
+$ ./OpenCAD
+```

icons/home.svg

@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg
+   viewBox="0 0 24 24"
+   fill="currentColor"
+   class="size-6"
+   version="1.1"
+   id="svg2"
+   sodipodi:docname="home.svg"
+   inkscape:version="1.4 (e7c3feb100, 2024-10-09)"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:svg="http://www.w3.org/2000/svg">
+  <defs
+     id="defs2" />
+  <sodipodi:namedview
+     id="namedview2"
+     pagecolor="#ffffff"
+     bordercolor="#000000"
+     borderopacity="0.25"
+     inkscape:showpageshadow="2"
+     inkscape:pageopacity="0.0"
+     inkscape:pagecheckerboard="0"
+     inkscape:deskcolor="#d1d1d1"
+     inkscape:zoom="14.574147"
+     inkscape:cx="6.9643869"
+     inkscape:cy="8.6797532"
+     inkscape:window-width="1440"
+     inkscape:window-height="831"
+     inkscape:window-x="0"
+     inkscape:window-y="0"
+     inkscape:window-maximized="1"
+     inkscape:current-layer="svg2" />
+  <path
+     d="M11.47 3.841a.75.75 0 0 1 1.06 0l8.69 8.69a.75.75 0 1 0 1.06-1.061l-8.689-8.69a2.25 2.25 0 0 0-3.182 0l-8.69 8.69a.75.75 0 1 0 1.061 1.06l8.69-8.689Z"
+     id="path1"
+     style="fill:#ffffff" />
+  <path
+     d="m12 5.432 8.159 8.159c.03.03.06.058.091.086v6.198c0 1.035-.84 1.875-1.875 1.875H15a.75.75 0 0 1-.75-.75v-4.5a.75.75 0 0 0-.75-.75h-3a.75.75 0 0 0-.75.75V21a.75.75 0 0 1-.75.75H5.625a1.875 1.875 0 0 1-1.875-1.875v-6.198a2.29 2.29 0 0 0 .091-.086L12 5.432Z"
+     id="path2"
+     style="fill:#ffffff" />
+</svg>

resources.qrc

@@ -7,11 +7,14 @@
 		<file>icons/circle.svg</file>
 		<file>icons/save-sketch.svg</file>
 		<file>icons/cursor.svg</file>
+		<file>icons/home.svg</file>
     </qresource>
     <qresource prefix="/shaders">
         <file alias="simple.vert">src/shaders/simple.vert</file>
         <file alias="simple.frag">src/shaders/simple.frag</file>
         <file alias="texture.vert">src/shaders/texture.vert</file>
         <file alias="texture.frag">src/shaders/texture.frag</file>
+        <file alias="lit.vert">src/shaders/lit.vert</file>
+        <file alias="lit.frag">src/shaders/lit.frag</file>
     </qresource>
 </RCC>

src/ApplicationController.cpp

@@ -2,6 +2,8 @@
 #include "Document.h"
 #include "SketchFeature.h"
 #include "SketchLine.h"
+#include "SketchRectangle.h"
+#include "SketchCircle.h"
 #include "MainWindow.h"
 
 #include <QInputDialog>
@@ -140,8 +142,25 @@ void ApplicationController::addLine(const gp_Pnt& start, const gp_Pnt& end)
     }
 }
 
+void ApplicationController::addRectangle(const gp_Pnt& corner1, const gp_Pnt& corner2)
+{
+    if (m_activeSketch) {
+        m_activeSketch->addObject(new SketchRectangle(corner1, corner2));
+    }
+}
+
+void ApplicationController::addCircle(const gp_Pnt& center, double radius)
+{
+    if (m_activeSketch) {
+        m_activeSketch->addObject(new SketchCircle(center, radius));
+    }
+}
+
 void ApplicationController::endSketch()
 {
+    if (m_activeSketch) {
+        m_activeSketch->buildShape();
+    }
     m_activeSketch = nullptr;
     setActiveTool(ToolType::None);
     emit sketchModeEnded();

src/ApplicationController.h

@@ -32,6 +32,8 @@ public:
 public slots:
     void setActiveTool(ToolType tool);
     void addLine(const gp_Pnt& start, const gp_Pnt& end);
+    void addRectangle(const gp_Pnt& corner1, const gp_Pnt& corner2);
+    void addCircle(const gp_Pnt& center, double radius);
     void newDocument();
     bool openDocument();
     bool saveDocument();

src/Camera.cpp

@@ -1,9 +1,14 @@
 #include "Camera.h"
+#include "ViewportWidget.h"
 #include <QApplication>
 #include <QWheelEvent>
+#include <QPropertyAnimation>
+#include <QParallelAnimationGroup>
+#include <QtMath>
 
 Camera::Camera(QObject *parent) : QObject(parent)
 {
+    m_lastPos = QPoint();
     // Set initial view to an isometric angle on the XY plane
     m_xRot = 30 * 16;
     m_yRot = -45 * 16;
@@ -12,29 +17,71 @@ Camera::Camera(QObject *parent) : QObject(parent)
     m_panY = 0.0f;
 }
 
-void Camera::processMouseMovement(QMouseEvent* event, const QPoint& lastPos)
+void Camera::mousePressEvent(QMouseEvent* event)
 {
-    int dx = event->pos().x() - lastPos.x();
-    int dy = event->pos().y() - lastPos.y();
+    m_lastPos = event->pos();
+}
 
-    if (event->buttons() & Qt::MiddleButton) {
+void Camera::mouseMoveEvent(QMouseEvent* event, int viewportHeight)
+{
+    int dx = event->pos().x() - m_lastPos.x();
+    int dy = event->pos().y() - m_lastPos.y();
+
+    if ((event->buttons() & Qt::MiddleButton) || (event->buttons() == (Qt::LeftButton | Qt::RightButton))) {
         if (QApplication::keyboardModifiers() & Qt::ShiftModifier) {
             // Pan
-            setPanX(m_panX + dx / 100.0f);
-            setPanY(m_panY - dy / 100.0f);
+            if (viewportHeight == 0) viewportHeight = 1;
+
+            // This logic is based on a 45-degree field of view.
+            float fov = 45.0f;
+            float dist = -m_zoom;
+
+            float world_height = 2.0f * dist * tan(qDegreesToRadians(fov / 2.0f));
+            float pixels_to_world = world_height / viewportHeight;
+
+            setPanX(m_panX + dx * pixels_to_world);
+            setPanY(m_panY - dy * pixels_to_world);
         } else {
             // Rotate
             setXRotation(m_xRot + 8 * dy);
             setYRotation(m_yRot + 8 * dx);
         }
     }
+    m_lastPos = event->pos();
 }
 
-void Camera::processWheel(QWheelEvent* event)
+void Camera::wheelEvent(QWheelEvent* event, const QVector3D& worldPos)
 {
     QPoint numDegrees = event->angleDelta() / 8;
     if (!numDegrees.isNull()) {
-        setZoom(m_zoom + numDegrees.y() / 5.0f);
+        // Make zoom speed proportional to distance, with a minimum speed and a cap.
+        // The factors are chosen to match the original zoom speed at the default zoom level.
+        float dist = -m_zoom;
+        dist = qMin(dist, 200.0f); // Cap distance to avoid crazy fast zoom out.
+        float zoomFactor = dist * 0.009f + 0.02f;
+        float zoomAmount = numDegrees.y() * zoomFactor;
+
+        float oldZoom = m_zoom;
+        float newZoom = oldZoom + zoomAmount;
+
+        QMatrix4x4 rotation;
+        rotation.rotate(m_xRot / 16.0f, 1, 0, 0);
+        rotation.rotate(m_yRot / 16.0f, 0, 1, 0);
+        QVector3D p_camera = rotation.map(worldPos);
+
+        if (std::abs(p_camera.z() + oldZoom) < 1e-6) {
+            setZoom(newZoom);
+            return;
+        }
+
+        float ratio = (p_camera.z() + newZoom) / (p_camera.z() + oldZoom);
+
+        float newPanX = (p_camera.x() + m_panX) * ratio - p_camera.x();
+        float newPanY = (p_camera.y() + m_panY) * ratio - p_camera.y();
+
+        setZoom(newZoom);
+        setPanX(newPanX);
+        setPanY(newPanY);
     }
 }
 
@@ -42,8 +89,15 @@ QMatrix4x4 Camera::modelViewMatrix() const
 {
     QMatrix4x4 model;
     model.translate(m_panX, m_panY, m_zoom);
+
+    if (m_isRotating) {
+        model.translate(m_rotationPivot);
+    }
     model.rotate(m_xRot / 16.0f, 1, 0, 0);
     model.rotate(m_yRot / 16.0f, 0, 1, 0);
+    if (m_isRotating) {
+        model.translate(-m_rotationPivot);
+    }
     return model;
 }
 
@@ -68,6 +122,14 @@ void Camera::setYRotation(float angle)
 float Camera::zoom() const { return m_zoom; }
 void Camera::setZoom(float value)
 {
+    const float max_dist = 5000.0f;
+    float remaining_dist_sq = max_dist * max_dist - m_panX * m_panX - m_panY * m_panY;
+    if (remaining_dist_sq < 0) {
+        remaining_dist_sq = 0;
+    }
+    float max_val = qSqrt(remaining_dist_sq);
+    value = qBound(-max_val, value, 0.0f); // Zoom is negative or zero
+
     if (value != m_zoom) {
         m_zoom = value;
         emit cameraChanged();
@@ -77,6 +139,14 @@ void Camera::setZoom(float value)
 float Camera::panX() const { return m_panX; }
 void Camera::setPanX(float value)
 {
+    const float max_dist = 5000.0f;
+    float remaining_dist_sq = max_dist * max_dist - m_panY * m_panY - m_zoom * m_zoom;
+    if (remaining_dist_sq < 0) {
+        remaining_dist_sq = 0;
+    }
+    float max_val = qSqrt(remaining_dist_sq);
+    value = qBound(-max_val, value, max_val);
+
     if (value != m_panX) {
         m_panX = value;
         emit cameraChanged();
@@ -86,6 +156,14 @@ void Camera::setPanX(float value)
 float Camera::panY() const { return m_panY; }
 void Camera::setPanY(float value)
 {
+    const float max_dist = 5000.0f;
+    float remaining_dist_sq = max_dist * max_dist - m_panX * m_panX - m_zoom * m_zoom;
+    if (remaining_dist_sq < 0) {
+        remaining_dist_sq = 0;
+    }
+    float max_val = qSqrt(remaining_dist_sq);
+    value = qBound(-max_val, value, max_val);
+
     if (value != m_panY) {
         m_panY = value;
         emit cameraChanged();
@@ -109,3 +187,264 @@ void Camera::restoreState()
     setPanY(m_savedPanY);
     setZoom(m_savedZoom);
 }
+
+void Camera::animateToPlaneView(int plane)
+{
+    float targetXRot = xRotation();
+    float targetYRot = yRotation();
+    switch (static_cast<ViewportWidget::SketchPlane>(plane)) {
+        case ViewportWidget::SketchPlane::XY: // Top view
+            targetXRot = 90 * 16;
+            targetYRot = 0;
+            break;
+        case ViewportWidget::SketchPlane::XZ: // Front view
+            targetXRot = 0;
+            targetYRot = 0;
+            break;
+        case ViewportWidget::SketchPlane::YZ: // Right view
+            targetXRot = 0;
+            targetYRot = -90 * 16;
+            break;
+        case ViewportWidget::SketchPlane::NONE:
+            break;
+    }
+
+    auto* animGroup = new QParallelAnimationGroup(this);
+
+    const float full_circle = 360.0f * 16.0f;
+
+    float currentXRot = xRotation();
+    float diffX = targetXRot - currentXRot;
+    diffX = fmod(diffX, full_circle);
+    if (diffX > full_circle / 2.0f) {
+        diffX -= full_circle;
+    } else if (diffX < -full_circle / 2.0f) {
+        diffX += full_circle;
+    }
+
+    auto* xRotAnim = new QPropertyAnimation(this, "xRotation");
+    xRotAnim->setDuration(300);
+    xRotAnim->setStartValue(currentXRot);
+    xRotAnim->setEndValue(currentXRot + diffX);
+    xRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(xRotAnim);
+
+    float currentYRot = yRotation();
+    float diffY = targetYRot - currentYRot;
+    diffY = fmod(diffY, full_circle);
+    if (diffY > full_circle / 2.0f) {
+        diffY -= full_circle;
+    } else if (diffY < -full_circle / 2.0f) {
+        diffY += full_circle;
+    }
+
+    auto* yRotAnim = new QPropertyAnimation(this, "yRotation");
+    yRotAnim->setDuration(300);
+    yRotAnim->setStartValue(currentYRot);
+    yRotAnim->setEndValue(currentYRot + diffY);
+    yRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(yRotAnim);
+
+    auto* panXAnim = new QPropertyAnimation(this, "panX");
+    panXAnim->setDuration(300);
+    panXAnim->setStartValue(panX());
+    panXAnim->setEndValue(0.0f);
+    panXAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(panXAnim);
+
+    auto* panYAnim = new QPropertyAnimation(this, "panY");
+    panYAnim->setDuration(300);
+    panYAnim->setStartValue(panY());
+    panYAnim->setEndValue(0.0f);
+    panYAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(panYAnim);
+
+    auto* zoomAnim = new QPropertyAnimation(this, "zoom");
+    zoomAnim->setDuration(300);
+    zoomAnim->setStartValue(zoom());
+    zoomAnim->setEndValue(-20.0f);
+    zoomAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(zoomAnim);
+
+    animGroup->start(QAbstractAnimation::DeleteWhenStopped);
+}
+
+void Camera::animateToHomeView()
+{
+    auto* animGroup = new QParallelAnimationGroup(this);
+
+    const float full_circle = 360.0f * 16.0f;
+
+    float currentXRot = xRotation();
+    float targetXRot = 30 * 16;
+    float diffX = targetXRot - currentXRot;
+    diffX = fmod(diffX, full_circle);
+    if (diffX > full_circle / 2.0f) {
+        diffX -= full_circle;
+    } else if (diffX < -full_circle / 2.0f) {
+        diffX += full_circle;
+    }
+
+    auto* xRotAnim = new QPropertyAnimation(this, "xRotation");
+    xRotAnim->setDuration(300);
+    xRotAnim->setStartValue(currentXRot);
+    xRotAnim->setEndValue(currentXRot + diffX);
+    xRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(xRotAnim);
+
+    float currentYRot = yRotation();
+    float targetYRot = -45 * 16;
+    float diffY = targetYRot - currentYRot;
+    diffY = fmod(diffY, full_circle);
+    if (diffY > full_circle / 2.0f) {
+        diffY -= full_circle;
+    } else if (diffY < -full_circle / 2.0f) {
+        diffY += full_circle;
+    }
+
+    auto* yRotAnim = new QPropertyAnimation(this, "yRotation");
+    yRotAnim->setDuration(300);
+    yRotAnim->setStartValue(currentYRot);
+    yRotAnim->setEndValue(currentYRot + diffY);
+    yRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(yRotAnim);
+
+    auto* panXAnim = new QPropertyAnimation(this, "panX");
+    panXAnim->setDuration(300);
+    panXAnim->setStartValue(panX());
+    panXAnim->setEndValue(0.0f);
+    panXAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(panXAnim);
+
+    auto* panYAnim = new QPropertyAnimation(this, "panY");
+    panYAnim->setDuration(300);
+    panYAnim->setStartValue(panY());
+    panYAnim->setEndValue(0.0f);
+    panYAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(panYAnim);
+
+    auto* zoomAnim = new QPropertyAnimation(this, "zoom");
+    zoomAnim->setDuration(300);
+    zoomAnim->setStartValue(zoom());
+    zoomAnim->setEndValue(-20.0f);
+    zoomAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(zoomAnim);
+
+    animGroup->start(QAbstractAnimation::DeleteWhenStopped);
+}
+
+void Camera::startRotation(const QVector3D& pivot)
+{
+    m_rotationPivot = pivot;
+    if (m_rotationPivot.length() > 1000.0f) {
+        m_rotationPivot = m_rotationPivot.normalized() * 1000.0f;
+    }
+    m_stableZoom = m_zoom;
+
+    QMatrix4x4 rotation;
+    rotation.rotate(m_xRot / 16.0f, 1, 0, 0);
+    rotation.rotate(m_yRot / 16.0f, 0, 1, 0);
+
+    QVector3D p_rotated = rotation.map(m_rotationPivot);
+    QVector3D p_diff = p_rotated - m_rotationPivot;
+
+    setPanX(m_panX + p_diff.x());
+    setPanY(m_panY + p_diff.y());
+    setZoom(m_zoom + p_diff.z());
+
+    m_isRotating = true;
+}
+
+void Camera::stopRotation()
+{
+    if (!m_isRotating) {
+        return;
+    }
+
+    QMatrix4x4 rotation;
+    rotation.rotate(m_xRot / 16.0f, 1, 0, 0);
+    rotation.rotate(m_yRot / 16.0f, 0, 1, 0);
+
+    QVector3D p_rotated = rotation.map(m_rotationPivot);
+    QVector3D p_diff = p_rotated - m_rotationPivot;
+
+    setPanX(m_panX - p_diff.x());
+    setPanY(m_panY - p_diff.y());
+    setZoom(m_zoom - p_diff.z());
+
+    m_isRotating = false;
+}
+
+void Camera::animateRestoreState()
+{
+    auto* animGroup = new QParallelAnimationGroup(this);
+
+    const float full_circle = 360.0f * 16.0f;
+
+    float currentXRot = xRotation();
+    float targetXRot = savedXRot();
+    float diffX = targetXRot - currentXRot;
+    diffX = fmod(diffX, full_circle);
+    if (diffX > full_circle / 2.0f) {
+        diffX -= full_circle;
+    } else if (diffX < -full_circle / 2.0f) {
+        diffX += full_circle;
+    }
+
+    auto* xRotAnim = new QPropertyAnimation(this, "xRotation");
+    xRotAnim->setDuration(300);
+    xRotAnim->setStartValue(currentXRot);
+    xRotAnim->setEndValue(currentXRot + diffX);
+    xRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(xRotAnim);
+
+    float currentYRot = yRotation();
+    float targetYRot = savedYRot();
+    float diffY = targetYRot - currentYRot;
+    diffY = fmod(diffY, full_circle);
+    if (diffY > full_circle / 2.0f) {
+        diffY -= full_circle;
+    } else if (diffY < -full_circle / 2.0f) {
+        diffY += full_circle;
+    }
+
+    auto* yRotAnim = new QPropertyAnimation(this, "yRotation");
+    yRotAnim->setDuration(300);
+    yRotAnim->setStartValue(currentYRot);
+    yRotAnim->setEndValue(currentYRot + diffY);
+    yRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(yRotAnim);
+
+    auto* panXAnim = new QPropertyAnimation(this, "panX");
+    panXAnim->setDuration(300);
+    panXAnim->setStartValue(panX());
+    panXAnim->setEndValue(savedPanX());
+    panXAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(panXAnim);
+
+    auto* panYAnim = new QPropertyAnimation(this, "panY");
+    panYAnim->setDuration(300);
+    panYAnim->setStartValue(panY());
+    panYAnim->setEndValue(savedPanY());
+    panYAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(panYAnim);
+
+    auto* zoomAnim = new QPropertyAnimation(this, "zoom");
+    zoomAnim->setDuration(300);
+    zoomAnim->setStartValue(zoom());
+    zoomAnim->setEndValue(savedZoom());
+    zoomAnim->setEasingCurve(QEasingCurve::InOutQuad);
+    animGroup->addAnimation(zoomAnim);
+
+    connect(animGroup, &QParallelAnimationGroup::finished, this, &Camera::restoreStateAnimationFinished);
+
+    animGroup->start(QAbstractAnimation::DeleteWhenStopped);
+}
+
+float Camera::uiCameraDistance() const
+{
+    if (m_isRotating) {
+        return m_stableZoom;
+    }
+    return m_zoom;
+}

src/Camera.h

@@ -19,8 +19,9 @@ class Camera : public QObject
 public:
     explicit Camera(QObject *parent = nullptr);
 
-    void processMouseMovement(QMouseEvent* event, const QPoint& lastPos);
-    void processWheel(QWheelEvent* event);
+    void mousePressEvent(QMouseEvent* event);
+    void mouseMoveEvent(QMouseEvent* event, int viewportHeight);
+    void wheelEvent(QWheelEvent* event, const QVector3D& worldPos);
 
     QMatrix4x4 modelViewMatrix() const;
 
@@ -38,6 +39,16 @@ public:
     void saveState();
     void restoreState();
 
+    void animateToPlaneView(int plane);
+    void animateRestoreState();
+    void animateToHomeView();
+
+    void startRotation(const QVector3D& pivot);
+    void stopRotation();
+    bool isRotating() const { return m_isRotating; }
+    const QVector3D& rotationPivot() const { return m_rotationPivot; }
+    float uiCameraDistance() const;
+
     float savedXRot() const { return m_savedXRot; }
     float savedYRot() const { return m_savedYRot; }
     float savedZoom() const { return m_savedZoom; }
@@ -46,14 +57,20 @@ public:
 
 signals:
     void cameraChanged();
+    void restoreStateAnimationFinished();
 
 private:
+    QPoint m_lastPos;
     float m_xRot;
     float m_yRot;
     float m_zoom;
     float m_panX;
     float m_panY;
 
+    QVector3D m_rotationPivot;
+    bool m_isRotating = false;
+    float m_stableZoom = 0;
+
     float m_savedXRot = 0;
     float m_savedYRot = 0;
     float m_savedZoom = -5.0f;

src/CircleTool.cpp

@@ -0,0 +1,267 @@
+#include "CircleTool.h"
+#include "ViewportWidget.h"
+#include "Camera.h"
+#include <QMouseEvent>
+#include <QKeyEvent>
+#include <QPainter>
+#include <QVector>
+#include <QOpenGLShaderProgram>
+#include <cmath>
+#include <QtMath>
+
+CircleTool::CircleTool(ViewportWidget* viewport)
+    : SketchTool(viewport)
+{
+}
+
+void CircleTool::activate()
+{
+    SketchTool::activate();
+    m_dimensionModes.clear();
+    m_dimensionModes << "diameter";
+    m_dimensionPropertyNames.clear();
+    m_dimensionPropertyNames["diameter"] = "diameterInput";
+
+    m_viewport->setProperty("diameterInput", "");
+    m_viewport->setProperty("dimensionEditMode", "diameter");
+}
+
+void CircleTool::mousePressEvent(QMouseEvent *event)
+{
+    gp_Pnt p;
+    if (!m_isDefining) {
+        if (m_viewport->isSnappingOrigin()) {
+            p.SetCoord(0, 0, 0);
+        } else if (m_viewport->isSnappingVertex()) {
+            p = m_viewport->snapVertex();
+        } else {
+            QVector3D worldPos = m_viewport->unproject(event->pos(), m_viewport->currentPlane());
+            p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+        }
+        m_centerPoint = p;
+        m_isDefining = true;
+
+        m_dimensionModes.clear();
+        m_dimensionModes << "diameter";
+        m_dimensionPropertyNames.clear();
+        m_dimensionPropertyNames["diameter"] = "diameterInput";
+
+        m_viewport->setProperty("diameterInput", "");
+        m_viewport->setProperty("dimensionEditMode", "diameter");
+    } else {
+        QVector3D worldPos;
+        QVector3D centerPos(m_centerPoint.X(), m_centerPoint.Y(), m_centerPoint.Z());
+
+        QString diameterInput = m_viewport->property("diameterInput").toString();
+        bool diameterFromInput = false;
+        double inputDiameter = 0;
+
+        if (!diameterInput.isEmpty()) {
+            bool ok;
+            inputDiameter = diameterInput.toDouble(&ok);
+            if (ok) diameterFromInput = true;
+        }
+
+        if (diameterFromInput) {
+            QVector3D mousePos = m_viewport->unproject(event->pos(), m_viewport->currentPlane());
+            QVector3D mouseDir = mousePos - centerPos;
+            if (mouseDir.lengthSquared() < 1e-9) {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY || m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                    mouseDir = QVector3D(1, 0, 0);
+                } else { // YZ
+                    mouseDir = QVector3D(0, 1, 0);
+                }
+            }
+            double radius = inputDiameter / 2.0;
+            worldPos = centerPos + mouseDir.normalized() * radius;
+        } else {
+            if (m_viewport->isSnappingOrigin()) {
+                worldPos.setX(0); worldPos.setY(0); worldPos.setZ(0);
+            } else if (m_viewport->isSnappingVertex()) {
+                worldPos = QVector3D(m_viewport->snapVertex().X(), m_viewport->snapVertex().Y(), m_viewport->snapVertex().Z());
+            } else {
+                worldPos = m_viewport->unproject(event->pos(), m_viewport->currentPlane());
+            }
+        }
+        p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+        emit m_viewport->circleAdded(m_centerPoint, m_centerPoint.Distance(p));
+        deactivate();
+    }
+}
+
+void CircleTool::mouseMoveEvent(QMouseEvent *event)
+{
+    // To be implemented
+}
+
+void CircleTool::finalizeCreation()
+{
+    QVector3D worldPos;
+    QVector3D centerPos(m_centerPoint.X(), m_centerPoint.Y(), m_centerPoint.Z());
+
+    QString diameterInput = m_viewport->property("diameterInput").toString();
+    bool diameterFromInput = false;
+    double inputDiameter = 0;
+
+    if (!diameterInput.isEmpty()) {
+        bool ok;
+        inputDiameter = diameterInput.toDouble(&ok);
+        if (ok) diameterFromInput = true;
+    }
+
+    if (diameterFromInput) {
+        QVector3D mousePos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+        QVector3D mouseDir = mousePos - centerPos;
+        if (mouseDir.lengthSquared() < 1e-9) {
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY || m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                mouseDir = QVector3D(1, 0, 0);
+            } else { // YZ
+                mouseDir = QVector3D(0, 1, 0);
+            }
+        }
+        double radius = inputDiameter / 2.0;
+        worldPos = centerPos + mouseDir.normalized() * radius;
+    } else {
+        worldPos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+    }
+
+    gp_Pnt p;
+    p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+
+    emit m_viewport->circleAdded(m_centerPoint, m_centerPoint.Distance(p));
+    deactivate();
+}
+
+void CircleTool::paintGL()
+{
+    if (m_isDefining) {
+        QVector<GLfloat> vertices;
+        QVector3D worldPos;
+        QVector3D centerPos(m_centerPoint.X(), m_centerPoint.Y(), m_centerPoint.Z());
+
+        QString diameterInput = m_viewport->property("diameterInput").toString();
+        bool diameterFromInput = false;
+        double inputDiameter = 0;
+
+        if (!diameterInput.isEmpty()) {
+            bool ok;
+            inputDiameter = diameterInput.toDouble(&ok);
+            if (ok) diameterFromInput = true;
+        }
+
+        QVector3D mousePos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+
+        double radius;
+        if (diameterFromInput) {
+            radius = inputDiameter / 2.0;
+        } else {
+            worldPos = mousePos;
+            if (m_viewport->isSnappingOrigin()) {
+                worldPos.setX(0); worldPos.setY(0); worldPos.setZ(0);
+            } else if (m_viewport->isSnappingVertex()) {
+                worldPos.setX(m_viewport->snapVertex().X()); worldPos.setY(m_viewport->snapVertex().Y()); worldPos.setZ(m_viewport->snapVertex().Z());
+            }
+            radius = (worldPos - centerPos).length();
+        }
+
+        const int segments = 64;
+        for (int i = 0; i < segments; ++i) {
+            double angle1 = i * 2.0 * M_PI / segments;
+            double angle2 = (i + 1) * 2.0 * M_PI / segments;
+
+            QVector3D p1, p2;
+
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                p1.setX(centerPos.x() + radius * qCos(angle1));
+                p1.setY(centerPos.y());
+                p1.setZ(centerPos.z() + radius * qSin(angle1));
+                p2.setX(centerPos.x() + radius * qCos(angle2));
+                p2.setY(centerPos.y());
+                p2.setZ(centerPos.z() + radius * qSin(angle2));
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                p1.setX(centerPos.x() + radius * qCos(angle1));
+                p1.setY(centerPos.y() + radius * qSin(angle1));
+                p1.setZ(centerPos.z());
+                p2.setX(centerPos.x() + radius * qCos(angle2));
+                p2.setY(centerPos.y() + radius * qSin(angle2));
+                p2.setZ(centerPos.z());
+            } else { // YZ
+                p1.setX(centerPos.x());
+                p1.setY(centerPos.y() + radius * qCos(angle1));
+                p1.setZ(centerPos.z() + radius * qSin(angle1));
+                p2.setX(centerPos.x());
+                p2.setY(centerPos.y() + radius * qCos(angle2));
+                p2.setZ(centerPos.z() + radius * qSin(angle2));
+            }
+            vertices << p1.x() << p1.y() << p1.z();
+            vertices << p2.x() << p2.y() << p2.z();
+        }
+
+        m_viewport->shaderProgram()->setUniformValue(m_viewport->colorLoc(), QVector4D(1.0f, 1.0f, 0.0f, 1.0f));
+        m_viewport->vbo().bind();
+        m_viewport->vbo().allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
+        glDrawArrays(GL_LINES, 0, segments * 2);
+    }
+}
+
+void CircleTool::paint2D(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection)
+{
+    if (m_isDefining) {
+        QVector3D worldPos;
+        QVector3D centerPos(m_centerPoint.X(), m_centerPoint.Y(), m_centerPoint.Z());
+
+        QString diameterInput = m_viewport->property("diameterInput").toString();
+        bool diameterFromInput = false;
+        double inputDiameter = 0;
+
+        if (!diameterInput.isEmpty()) {
+            bool ok;
+            inputDiameter = diameterInput.toDouble(&ok);
+            if (ok) diameterFromInput = true;
+        }
+
+        QVector3D mousePos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+        QVector3D edgePos;
+        double diameter;
+
+        if (diameterFromInput) {
+            diameter = inputDiameter;
+            QVector3D mouseDir = mousePos - centerPos;
+            if (mouseDir.lengthSquared() < 1e-9) {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY || m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                    mouseDir = QVector3D(1, 0, 0);
+                } else { // YZ
+                    mouseDir = QVector3D(0, 1, 0);
+                }
+            }
+            edgePos = centerPos + mouseDir.normalized() * (diameter / 2.0);
+        } else {
+            edgePos = mousePos;
+            if (m_viewport->isSnappingOrigin()) {
+                edgePos.setX(0); edgePos.setY(0); edgePos.setZ(0);
+            } else if (m_viewport->isSnappingVertex()) {
+                edgePos.setX(m_viewport->snapVertex().X()); edgePos.setY(m_viewport->snapVertex().Y()); edgePos.setZ(m_viewport->snapVertex().Z());
+            }
+            diameter = (edgePos - centerPos).length() * 2.0;
+        }
+
+        painter.setRenderHint(QPainter::Antialiasing);
+        QFontMetrics fm(painter.font());
+
+        // Diameter dimension
+        QVector3D diameterTextPos3D = (centerPos + edgePos) / 2.0f;
+        QVector3D screenPosD = m_viewport->project(diameterTextPos3D, modelView, projection, m_viewport->rect());
+        if (screenPosD.z() < 1.0f) {
+            QString diameterText = diameterFromInput ? diameterInput : QString::number(diameter, 'f', 2);
+            QRect textRect = fm.boundingRect(diameterText + "__");
+            textRect.moveCenter(screenPosD.toPoint());
+            if (m_viewport->property("dimensionEditMode").toString() == "diameter") {
+                painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(64, 128, 255));
+            } else {
+                painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(50, 50, 50));
+            }
+            painter.setPen(Qt::white);
+            painter.drawText(textRect, Qt::AlignCenter, diameterText);
+        }
+    }
+}

src/CircleTool.h

@@ -0,0 +1,28 @@
+#ifndef CIRCLETOOL_H
+#define CIRCLETOOL_H
+
+#include "SketchTool.h"
+#include <gp_Pnt.hxx>
+
+class CircleTool : public SketchTool
+{
+    Q_OBJECT
+public:
+    explicit CircleTool(ViewportWidget* viewport);
+
+    void mousePressEvent(QMouseEvent *event) override;
+    void mouseMoveEvent(QMouseEvent *event) override;
+
+    void paintGL() override;
+    void paint2D(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection) override;
+
+    void activate() override;
+
+protected:
+    void finalizeCreation() override;
+
+private:
+    gp_Pnt m_centerPoint;
+};
+
+#endif // CIRCLETOOL_H

src/LineTool.cpp

@@ -0,0 +1,852 @@
+#include "LineTool.h"
+#include "ViewportWidget.h"
+#include "Camera.h"
+#include <QMouseEvent>
+#include <QKeyEvent>
+#include <QPainter>
+#include <QOpenGLShaderProgram>
+#include <QtMath>
+
+LineTool::LineTool(ViewportWidget* viewport)
+    : SketchTool(viewport)
+{
+}
+
+void LineTool::activate()
+{
+    SketchTool::activate();
+    m_dimensionModes << "length" << "angle";
+    m_dimensionPropertyNames["length"] = "dimensionInput";
+    m_dimensionPropertyNames["angle"] = "angleInput";
+
+    m_viewport->setProperty("dimensionInput", "");
+    m_viewport->setProperty("angleInput", "");
+    m_viewport->setProperty("dimensionEditMode", "length");
+    m_viewport->setProperty("isChainedLine", false);
+}
+
+void LineTool::mousePressEvent(QMouseEvent *event)
+{
+    gp_Pnt p;
+    QString dimInput = m_viewport->property("dimensionInput").toString();
+    QString angleInput = m_viewport->property("angleInput").toString();
+    bool lengthFromInput = false;
+    bool angleFromInput = false;
+    double inputLength = 0;
+    double inputAngleDegrees = 0;
+
+    if (m_isDefining) {
+        if (!dimInput.isEmpty()) {
+            bool ok;
+            inputLength = dimInput.toDouble(&ok);
+            if (ok) lengthFromInput = true;
+        }
+        if (!angleInput.isEmpty()) {
+            bool ok;
+            inputAngleDegrees = angleInput.toDouble(&ok);
+            if (ok) angleFromInput = true;
+        }
+    }
+
+    if (m_isDefining && (lengthFromInput || angleFromInput)) {
+        QVector3D worldPos;
+        QVector3D startPos(m_firstLinePoint.X(), m_firstLinePoint.Y(), m_firstLinePoint.Z());
+
+        if (angleFromInput) {
+            QVector3D refDir;
+            if (m_viewport->property("isChainedLine").toBool()) {
+                refDir = m_viewport->property("previousLineDirection").value<QVector3D>();
+            } else {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY || m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) refDir = QVector3D(1, 0, 0);
+                else refDir = QVector3D(0, 0, -1);
+            }
+            QVector3D currentMouseWorldPos = m_viewport->unproject(event->pos(), m_viewport->currentPlane());
+            QVector3D mouseVec = currentMouseWorldPos - startPos;
+            double mouseAngle;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) mouseAngle = qRadiansToDegrees(atan2(mouseVec.z(), mouseVec.x()));
+            else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) mouseAngle = qRadiansToDegrees(atan2(mouseVec.y(), mouseVec.x()));
+            else mouseAngle = qRadiansToDegrees(atan2(mouseVec.z(), mouseVec.y()));
+            double refAngle;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) refAngle = qRadiansToDegrees(atan2(refDir.z(), refDir.x()));
+            else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) refAngle = qRadiansToDegrees(atan2(refDir.y(), refDir.x()));
+            else refAngle = qRadiansToDegrees(atan2(refDir.z(), refDir.y()));
+            double relativeMouseAngle = mouseAngle - refAngle;
+            while (relativeMouseAngle <= -180.0) relativeMouseAngle += 360.0;
+            while (relativeMouseAngle > 180.0) relativeMouseAngle -= 360.0;
+            double snappedAngle = 0;
+            if (relativeMouseAngle >= 0 && relativeMouseAngle < 90) { // Quadrant 1
+                snappedAngle = inputAngleDegrees;
+            } else if (relativeMouseAngle >= 90 && relativeMouseAngle <= 180) { // Quadrant 2
+                snappedAngle = 180.0 - inputAngleDegrees;
+            } else if (relativeMouseAngle < -90) { // Quadrant 3
+                snappedAngle = -180.0 + inputAngleDegrees;
+            } else { // Quadrant 4
+                snappedAngle = -inputAngleDegrees;
+            }
+            double finalAngleRad = qDegreesToRadians(refAngle + snappedAngle);
+            QVector3D finalDir;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) finalDir = QVector3D(cos(finalAngleRad), 0, sin(finalAngleRad));
+            else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) finalDir = QVector3D(cos(finalAngleRad), sin(finalAngleRad), 0);
+            else finalDir = QVector3D(0, cos(finalAngleRad), sin(finalAngleRad));
+            double lineLength;
+            if (lengthFromInput) lineLength = inputLength;
+            else {
+                lineLength = QVector3D::dotProduct(mouseVec, finalDir);
+                if (lineLength < 0) lineLength = 0;
+            }
+            worldPos = startPos + lineLength * finalDir;
+        } else if (lengthFromInput) {
+            QVector3D currentMouseWorldPos = m_viewport->unproject(event->pos(), m_viewport->currentPlane());
+            QVector3D dir = (currentMouseWorldPos - startPos);
+            if (dir.length() > 1e-6) {
+                dir.normalize();
+                worldPos = startPos + inputLength * dir;
+            } else {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY || m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) worldPos = startPos + QVector3D(inputLength, 0, 0);
+                else worldPos = startPos + QVector3D(0, inputLength, 0);
+            }
+        }
+        p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+    } else {
+        if (m_viewport->isSnappingOrigin()) {
+            p.SetCoord(0, 0, 0);
+        } else if (m_viewport->isSnappingVertex()) {
+            p = m_viewport->snapVertex();
+        } else {
+            QVector3D worldPos = m_viewport->unproject(event->pos(), m_viewport->currentPlane());
+            if (m_viewport->isSnappingHorizontal()) {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) worldPos.setZ(m_firstLinePoint.Z());
+                else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) worldPos.setY(m_firstLinePoint.Y());
+                else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::YZ) worldPos.setZ(m_firstLinePoint.Z());
+            } else if (m_viewport->isSnappingVertical()) {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) worldPos.setX(m_firstLinePoint.X());
+                else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) worldPos.setX(m_firstLinePoint.X());
+                else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::YZ) worldPos.setY(m_firstLinePoint.Y());
+            }
+            p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+        }
+    }
+
+    if (!m_isDefining) {
+        m_firstLinePoint = p;
+        m_isDefining = true;
+        m_viewport->setProperty("dimensionInput", QVariant(""));
+        m_viewport->setProperty("angleInput", QVariant(""));
+        m_viewport->setProperty("dimensionEditMode", "length");
+        m_viewport->setProperty("isChainedLine", false);
+    } else {
+        QVector3D start(m_firstLinePoint.X(), m_firstLinePoint.Y(), m_firstLinePoint.Z());
+        QVector3D end(p.X(), p.Y(), p.Z());
+        m_viewport->setProperty("previousLineDirection", QVariant::fromValue((end - start).normalized()));
+
+        m_viewport->addLine(m_firstLinePoint, p);
+        m_firstLinePoint = p;
+        m_viewport->setProperty("dimensionInput", QVariant(""));
+        m_viewport->setProperty("angleInput", QVariant(""));
+        m_viewport->setProperty("dimensionEditMode", "length");
+        m_viewport->setProperty("isChainedLine", true);
+    }
+}
+
+void LineTool::mouseMoveEvent(QMouseEvent *event)
+{
+    bool oldIsSnappingHorizontal = m_viewport->isSnappingHorizontal();
+    bool oldIsSnappingVertical = m_viewport->isSnappingVertical();
+    m_viewport->setSnappingHorizontal(false);
+    m_viewport->setSnappingVertical(false);
+
+    if (m_isDefining && !m_viewport->isSnappingOrigin() && !m_viewport->isSnappingVertex()) {
+        QVector3D worldPos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+        QVector3D startPos(m_firstLinePoint.X(), m_firstLinePoint.Y(), m_firstLinePoint.Z());
+        QVector3D delta = worldPos - startPos;
+
+        if (delta.length() > 1e-6) {
+            const double snapAngleThreshold = qDegreesToRadians(2.0);
+            double angle = 0;
+
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                angle = atan2(delta.z(), delta.x());
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                angle = atan2(delta.y(), delta.x());
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::YZ) {
+                angle = atan2(delta.z(), delta.y());
+            }
+
+            if (qAbs(sin(angle)) < sin(snapAngleThreshold)) {
+                m_viewport->setSnappingHorizontal(true);
+            } else if (qAbs(cos(angle)) < sin(snapAngleThreshold)) {
+                m_viewport->setSnappingVertical(true);
+            }
+        }
+    }
+
+    if (oldIsSnappingHorizontal != m_viewport->isSnappingHorizontal() || oldIsSnappingVertical != m_viewport->isSnappingVertical()) {
+        m_viewport->update();
+    }
+}
+
+void LineTool::finalizeCreation()
+{
+    QVector3D worldPos;
+    QVector3D startPos(m_firstLinePoint.X(), m_firstLinePoint.Y(), m_firstLinePoint.Z());
+    // This is duplicated from paintGL to ensure consistent line creation
+    QString dimInput = m_viewport->property("dimensionInput").toString();
+    QString angleInput = m_viewport->property("angleInput").toString();
+    bool lengthFromInput = false;
+    bool angleFromInput = false;
+    double inputLength = 0;
+    double inputAngleDegrees = 0;
+
+    if (!dimInput.isEmpty()) {
+        bool ok;
+        inputLength = dimInput.toDouble(&ok);
+        if (ok) lengthFromInput = true;
+    }
+    if (!angleInput.isEmpty()) {
+        bool ok;
+        inputAngleDegrees = angleInput.toDouble(&ok);
+        if (ok) angleFromInput = true;
+    }
+
+    if (angleFromInput) {
+        QVector3D refDir;
+        if (m_viewport->property("isChainedLine").toBool()) {
+            refDir = m_viewport->property("previousLineDirection").value<QVector3D>();
+        } else {
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY || m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) refDir = QVector3D(1, 0, 0);
+            else refDir = QVector3D(0, 0, -1);
+        }
+        QVector3D currentMouseWorldPos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+        QVector3D mouseVec = currentMouseWorldPos - startPos;
+        double mouseAngle;
+        if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) mouseAngle = qRadiansToDegrees(atan2(mouseVec.z(), mouseVec.x()));
+        else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) mouseAngle = qRadiansToDegrees(atan2(mouseVec.y(), mouseVec.x()));
+        else mouseAngle = qRadiansToDegrees(atan2(mouseVec.z(), mouseVec.y()));
+        double refAngle;
+        if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) refAngle = qRadiansToDegrees(atan2(refDir.z(), refDir.x()));
+        else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) refAngle = qRadiansToDegrees(atan2(refDir.y(), refDir.x()));
+        else refAngle = qRadiansToDegrees(atan2(refDir.z(), refDir.y()));
+        double relativeMouseAngle = mouseAngle - refAngle;
+        while (relativeMouseAngle <= -180.0) relativeMouseAngle += 360.0;
+        while (relativeMouseAngle > 180.0) relativeMouseAngle -= 360.0;
+        double snappedAngle = 0;
+        if (relativeMouseAngle >= 0 && relativeMouseAngle < 90) { // Quadrant 1
+            snappedAngle = inputAngleDegrees;
+        } else if (relativeMouseAngle >= 90 && relativeMouseAngle <= 180) { // Quadrant 2
+            snappedAngle = 180.0 - inputAngleDegrees;
+        } else if (relativeMouseAngle < -90) { // Quadrant 3
+            snappedAngle = -180.0 + inputAngleDegrees;
+        } else { // Quadrant 4
+            snappedAngle = -inputAngleDegrees;
+        }
+        double finalAngleRad = qDegreesToRadians(refAngle + snappedAngle);
+        QVector3D finalDir;
+        if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) finalDir = QVector3D(cos(finalAngleRad), 0, sin(finalAngleRad));
+        else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) finalDir = QVector3D(cos(finalAngleRad), sin(finalAngleRad), 0);
+        else finalDir = QVector3D(0, cos(finalAngleRad), sin(finalAngleRad));
+        double lineLength;
+        if (lengthFromInput) lineLength = inputLength;
+        else {
+            lineLength = QVector3D::dotProduct(mouseVec, finalDir);
+            if (lineLength < 0) lineLength = 0;
+        }
+        worldPos = startPos + lineLength * finalDir;
+    } else if (lengthFromInput) {
+        QVector3D currentMouseWorldPos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+        QVector3D dir = (currentMouseWorldPos - startPos);
+        if (dir.length() > 1e-6) {
+            dir.normalize();
+            worldPos = startPos + inputLength * dir;
+        } else {
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY || m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) worldPos = startPos + QVector3D(inputLength, 0, 0);
+            else worldPos = startPos + QVector3D(0, inputLength, 0);
+        }
+    } else {
+        worldPos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+    }
+
+    gp_Pnt p;
+    p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+
+    QVector3D prevDir = (worldPos - startPos).normalized();
+    m_viewport->setProperty("previousLineDirection", QVariant::fromValue(prevDir));
+
+    m_viewport->addLine(m_firstLinePoint, p);
+    m_firstLinePoint = p;
+    m_viewport->setProperty("dimensionInput", QVariant(""));
+    m_viewport->setProperty("angleInput", QVariant(""));
+    m_viewport->setProperty("dimensionEditMode", "length");
+    m_viewport->setProperty("isChainedLine", true);
+}
+
+void LineTool::paintGL()
+{
+    if (m_isDefining) {
+        QVector<GLfloat> vertices;
+        QVector3D worldPos;
+        QVector3D startPos(m_firstLinePoint.X(), m_firstLinePoint.Y(), m_firstLinePoint.Z());
+
+        QString dimInput = m_viewport->property("dimensionInput").toString();
+        QString angleInput = m_viewport->property("angleInput").toString();
+        bool lengthFromInput = false;
+        bool angleFromInput = false;
+        double inputLength = 0;
+        double inputAngleDegrees = 0;
+
+        if (!dimInput.isEmpty()) {
+            bool ok;
+            inputLength = dimInput.toDouble(&ok);
+            if (ok) lengthFromInput = true;
+        }
+        if (!angleInput.isEmpty()) {
+            bool ok;
+            inputAngleDegrees = angleInput.toDouble(&ok);
+            if (ok) angleFromInput = true;
+        }
+
+        if (angleFromInput) {
+            QVector3D refDir;
+            if (m_viewport->property("isChainedLine").toBool()) {
+                refDir = m_viewport->property("previousLineDirection").value<QVector3D>();
+            } else {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY || m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                    refDir = QVector3D(1, 0, 0);
+                } else { // YZ
+                    refDir = QVector3D(0, 0, -1);
+                }
+            }
+
+            QVector3D currentMouseWorldPos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+            QVector3D mouseVec = currentMouseWorldPos - startPos;
+
+            // Quadrant snapping
+            double mouseAngle;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) mouseAngle = qRadiansToDegrees(atan2(mouseVec.z(), mouseVec.x()));
+            else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) mouseAngle = qRadiansToDegrees(atan2(mouseVec.y(), mouseVec.x()));
+            else mouseAngle = qRadiansToDegrees(atan2(mouseVec.z(), mouseVec.y()));
+
+            double refAngle;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) refAngle = qRadiansToDegrees(atan2(refDir.z(), refDir.x()));
+            else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) refAngle = qRadiansToDegrees(atan2(refDir.y(), refDir.x()));
+            else refAngle = qRadiansToDegrees(atan2(refDir.z(), refDir.y()));
+
+            double relativeMouseAngle = mouseAngle - refAngle;
+            while (relativeMouseAngle <= -180.0) relativeMouseAngle += 360.0;
+            while (relativeMouseAngle > 180.0) relativeMouseAngle -= 360.0;
+
+            double snappedAngle = 0;
+            if (relativeMouseAngle >= 0 && relativeMouseAngle < 90) { // Quadrant 1
+                snappedAngle = inputAngleDegrees;
+            } else if (relativeMouseAngle >= 90 && relativeMouseAngle <= 180) { // Quadrant 2
+                snappedAngle = 180.0 - inputAngleDegrees;
+            } else if (relativeMouseAngle < -90) { // Quadrant 3
+                snappedAngle = -180.0 + inputAngleDegrees;
+            } else { // Quadrant 4
+                snappedAngle = -inputAngleDegrees;
+            }
+
+            double finalAngleRad = qDegreesToRadians(refAngle + snappedAngle);
+            QVector3D finalDir;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) finalDir = QVector3D(cos(finalAngleRad), 0, sin(finalAngleRad));
+            else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) finalDir = QVector3D(cos(finalAngleRad), sin(finalAngleRad), 0);
+            else finalDir = QVector3D(0, cos(finalAngleRad), sin(finalAngleRad));
+
+            double lineLength;
+            if (lengthFromInput) {
+                lineLength = inputLength;
+            } else {
+                lineLength = QVector3D::dotProduct(mouseVec, finalDir);
+                 if (lineLength < 0) lineLength = 0;
+            }
+            worldPos = startPos + lineLength * finalDir;
+
+        } else if (lengthFromInput) {
+            QVector3D currentMouseWorldPos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+            QVector3D dir = (currentMouseWorldPos - startPos);
+            if (dir.length() > 1e-6) {
+                dir.normalize();
+                worldPos = startPos + inputLength * dir;
+            } else {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY || m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                    worldPos = startPos + QVector3D(inputLength, 0, 0);
+                } else {
+                    worldPos = startPos + QVector3D(0, inputLength, 0);
+                }
+            }
+        } else {
+            worldPos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+            if (m_viewport->isSnappingOrigin()) {
+                worldPos.setX(0); worldPos.setY(0); worldPos.setZ(0);
+            } else if (m_viewport->isSnappingVertex()) {
+                worldPos.setX(m_viewport->snapVertex().X()); worldPos.setY(m_viewport->snapVertex().Y()); worldPos.setZ(m_viewport->snapVertex().Z());
+            } else if (m_viewport->isSnappingHorizontal()) {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) worldPos.setZ(m_firstLinePoint.Z());
+                else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) worldPos.setY(m_firstLinePoint.Y());
+                else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::YZ) worldPos.setZ(m_firstLinePoint.Z());
+            } else if (m_viewport->isSnappingVertical()) {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) worldPos.setX(m_firstLinePoint.X());
+                else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) worldPos.setX(m_firstLinePoint.X());
+                else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::YZ) worldPos.setY(m_firstLinePoint.Y());
+            }
+        }
+
+        vertices << m_firstLinePoint.X() << m_firstLinePoint.Y() << m_firstLinePoint.Z();
+        vertices << worldPos.x() << worldPos.y() << worldPos.z();
+
+        m_viewport->shaderProgram()->setUniformValue(m_viewport->colorLoc(), QVector4D(1.0f, 1.0f, 0.0f, 1.0f));
+        m_viewport->vbo().bind();
+        m_viewport->vbo().allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
+        glDrawArrays(GL_LINES, 0, 2);
+
+        // Draw dimension line
+        QVector3D lineVec = worldPos - startPos;
+        float lineLength = lineVec.length();
+
+        if (lineLength > 1e-6) {
+            double refAngle, lineAngle, angleDiff;
+            {
+                QVector3D refDir;
+                if (m_viewport->property("isChainedLine").toBool()) {
+                    refDir = m_viewport->property("previousLineDirection").value<QVector3D>();
+                } else {
+                    if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY || m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) refDir = QVector3D(1, 0, 0);
+                    else refDir = QVector3D(0, 0, -1);
+                }
+
+                if (angleFromInput) {
+                    QVector3D currentMouseWorldPos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+                    QVector3D mouseVec = currentMouseWorldPos - startPos;
+
+                    double mouseAngle;
+                    if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) mouseAngle = qRadiansToDegrees(atan2(mouseVec.z(), mouseVec.x()));
+                    else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) mouseAngle = qRadiansToDegrees(atan2(mouseVec.y(), mouseVec.x()));
+                    else mouseAngle = qRadiansToDegrees(atan2(mouseVec.z(), mouseVec.y()));
+
+                    double refAngleForQuadrant;
+                    if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) refAngleForQuadrant = qRadiansToDegrees(atan2(refDir.z(), refDir.x()));
+                    else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) refAngleForQuadrant = qRadiansToDegrees(atan2(refDir.y(), refDir.x()));
+                    else refAngleForQuadrant = qRadiansToDegrees(atan2(refDir.z(), refDir.y()));
+
+                    double relativeMouseAngle = mouseAngle - refAngleForQuadrant;
+                    while (relativeMouseAngle <= -180.0) relativeMouseAngle += 360.0;
+                    while (relativeMouseAngle > 180.0) relativeMouseAngle -= 360.0;
+
+                    if (relativeMouseAngle >= 90 || relativeMouseAngle < -90) {
+                        refDir = -refDir;
+                    }
+                } else {
+                    if (m_viewport->property("isChainedLine").toBool()) {
+                        refDir = -refDir;
+                    }
+                }
+
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                    refAngle = atan2(refDir.z(), refDir.x());
+                    lineAngle = atan2(lineVec.z(), lineVec.x());
+                } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                    refAngle = atan2(refDir.y(), refDir.x());
+                    lineAngle = atan2(lineVec.y(), lineVec.x());
+                } else { // YZ
+                    refAngle = atan2(refDir.z(), refDir.y());
+                    lineAngle = atan2(lineVec.z(), lineVec.y());
+                }
+
+                angleDiff = lineAngle - refAngle;
+                while (angleDiff <= -M_PI) angleDiff += 2 * M_PI;
+                while (angleDiff > M_PI) angleDiff -= 2 * M_PI;
+                lineAngle = refAngle + angleDiff;
+            }
+
+            vertices.clear();
+
+            QVector3D perpVec;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                perpVec = QVector3D(-lineVec.z(), 0, lineVec.x()).normalized();
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                perpVec = QVector3D(-lineVec.y(), lineVec.x(), 0).normalized();
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::YZ) {
+                perpVec = QVector3D(0, -lineVec.z(), lineVec.y()).normalized();
+            }
+
+            if (angleDiff < 0) {
+                perpVec = -perpVec;
+            }
+
+            float offset = 0.05f * -m_viewport->camera()->zoom();
+            QVector3D dimStart = startPos + offset * perpVec;
+            QVector3D dimEnd = worldPos + offset * perpVec;
+
+            vertices << dimStart.x() << dimStart.y() << dimStart.z();
+            vertices << dimEnd.x() << dimEnd.y() << dimEnd.z();
+
+            float arrowLength = 0.02f * -m_viewport->camera()->zoom();
+            float arrowWidth = 0.005f * -m_viewport->camera()->zoom();
+            QVector3D lineDir = lineVec.normalized();
+
+            QVector3D arrow_base_end = dimEnd - arrowLength * lineDir;
+            QVector3D arrowP1_end = arrow_base_end + arrowWidth * perpVec;
+            QVector3D arrowP2_end = arrow_base_end - arrowWidth * perpVec;
+            vertices << dimEnd.x() << dimEnd.y() << dimEnd.z();
+            vertices << arrowP1_end.x() << arrowP1_end.y() << arrowP1_end.z();
+            vertices << dimEnd.x() << dimEnd.y() << dimEnd.z();
+            vertices << arrowP2_end.x() << arrowP2_end.y() << arrowP2_end.z();
+
+            QVector3D arrow_base_start = dimStart + arrowLength * lineDir;
+            QVector3D arrowP1_start = arrow_base_start + arrowWidth * perpVec;
+            QVector3D arrowP2_start = arrow_base_start - arrowWidth * perpVec;
+            vertices << dimStart.x() << dimStart.y() << dimStart.z();
+            vertices << arrowP1_start.x() << arrowP1_start.y() << arrowP1_start.z();
+            vertices << dimStart.x() << dimStart.y() << dimStart.z();
+            vertices << arrowP2_start.x() << arrowP2_start.y() << arrowP2_start.z();
+
+            m_viewport->shaderProgram()->setUniformValue(m_viewport->colorLoc(), QVector4D(0.7f, 0.7f, 0.7f, 1.0f));
+            glLineWidth(1.0f);
+            m_viewport->vbo().bind();
+            m_viewport->vbo().allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
+            glDrawArrays(GL_LINES, 0, vertices.size() / 3);
+            glLineWidth(2.0f);
+
+            // Draw angle dimension
+            vertices.clear();
+            const int numSegments = 30;
+            const float radius = 0.1f * -m_viewport->camera()->zoom();
+            for (int i = 0; i <= numSegments; ++i) {
+                double angle = refAngle + (lineAngle - refAngle) * i / numSegments;
+                QVector3D p;
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) p = startPos + radius * QVector3D(cos(angle), 0, sin(angle));
+                else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) p = startPos + radius * QVector3D(cos(angle), sin(angle), 0);
+                else p = startPos + radius * QVector3D(0, cos(angle), sin(angle));
+                vertices << p.x() << p.y() << p.z();
+            }
+            glLineWidth(1.0f);
+            m_viewport->vbo().bind();
+            m_viewport->vbo().allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
+            glDrawArrays(GL_LINE_STRIP, 0, vertices.size() / 3);
+
+            // Arrowheads for arc
+            QVector<GLfloat> arrowVertices;
+            float arcArrowLength = 0.02f * -m_viewport->camera()->zoom();
+            float arcArrowWidth = 0.005f * -m_viewport->camera()->zoom();
+
+            double sign = (angleDiff >= 0) ? 1.0 : -1.0;
+
+            // End arrowhead
+            QVector3D endPoint(vertices[vertices.size()-3], vertices[vertices.size()-2], vertices[vertices.size()-1]);
+            double endAngle = lineAngle;
+            QVector3D radialDir_end, tangentDir_end;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                radialDir_end = QVector3D(cos(endAngle), 0, sin(endAngle));
+                tangentDir_end = QVector3D(-sin(endAngle), 0, cos(endAngle));
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                radialDir_end = QVector3D(cos(endAngle), sin(endAngle), 0);
+                tangentDir_end = QVector3D(-sin(endAngle), cos(endAngle), 0);
+            } else {
+                radialDir_end = QVector3D(0, cos(endAngle), sin(endAngle));
+                tangentDir_end = QVector3D(0, -sin(endAngle), cos(endAngle));
+            }
+            QVector3D arc_arrow_base_end = endPoint - sign * arcArrowLength * tangentDir_end;
+            QVector3D arc_arrowP1_end = arc_arrow_base_end + arcArrowWidth * radialDir_end;
+            QVector3D arc_arrowP2_end = arc_arrow_base_end - arcArrowWidth * radialDir_end;
+            arrowVertices << endPoint.x() << endPoint.y() << endPoint.z() << arc_arrowP1_end.x() << arc_arrowP1_end.y() << arc_arrowP1_end.z();
+            arrowVertices << endPoint.x() << endPoint.y() << endPoint.z() << arc_arrowP2_end.x() << arc_arrowP2_end.y() << arc_arrowP2_end.z();
+
+            // Start arrowhead
+            QVector3D startPoint(vertices[0], vertices[1], vertices[2]);
+            double startAngle = refAngle;
+            QVector3D radialDir_start, tangentDir_start;
+             if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                radialDir_start = QVector3D(cos(startAngle), 0, sin(startAngle));
+                tangentDir_start = QVector3D(-sin(startAngle), 0, cos(startAngle));
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                radialDir_start = QVector3D(cos(startAngle), sin(startAngle), 0);
+                tangentDir_start = QVector3D(-sin(startAngle), cos(startAngle), 0);
+            } else {
+                radialDir_start = QVector3D(0, cos(startAngle), sin(startAngle));
+                tangentDir_start = QVector3D(0, -sin(startAngle), cos(startAngle));
+            }
+            QVector3D arc_arrow_base_start = startPoint + sign * arcArrowLength * tangentDir_start;
+            QVector3D arc_arrowP1_start = arc_arrow_base_start + arcArrowWidth * radialDir_start;
+            QVector3D arc_arrowP2_start = arc_arrow_base_start - arcArrowWidth * radialDir_start;
+            arrowVertices << startPoint.x() << startPoint.y() << startPoint.z() << arc_arrowP1_start.x() << arc_arrowP1_start.y() << arc_arrowP1_start.z();
+            arrowVertices << startPoint.x() << startPoint.y() << startPoint.z() << arc_arrowP2_start.x() << arc_arrowP2_start.y() << arc_arrowP2_start.z();
+
+            m_viewport->vbo().bind();
+            m_viewport->vbo().allocate(arrowVertices.constData(), arrowVertices.size() * sizeof(GLfloat));
+            glDrawArrays(GL_LINES, 0, arrowVertices.size() / 3);
+            glLineWidth(2.0f);
+        }
+
+        if (!lengthFromInput && !angleFromInput && (m_viewport->isSnappingHorizontal() || m_viewport->isSnappingVertical())) {
+            vertices.clear();
+            QVector3D startPos(m_firstLinePoint.X(), m_firstLinePoint.Y(), m_firstLinePoint.Z());
+            QVector3D midPoint = (startPos + worldPos) / 2.0;
+            const float indicatorSize = 0.02f * -m_viewport->camera()->zoom();
+            const float indicatorOffset = 0.02f * -m_viewport->camera()->zoom();
+            if (m_viewport->isSnappingHorizontal()) {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                    vertices << midPoint.x() - indicatorSize << midPoint.y() << midPoint.z() + indicatorOffset;
+                    vertices << midPoint.x() + indicatorSize << midPoint.y() << midPoint.z() + indicatorOffset;
+                } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                    vertices << midPoint.x() - indicatorSize << midPoint.y() + indicatorOffset << midPoint.z();
+                    vertices << midPoint.x() + indicatorSize << midPoint.y() + indicatorOffset << midPoint.z();
+                } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::YZ) {
+                    vertices << midPoint.x() << midPoint.y() - indicatorSize << midPoint.z() + indicatorOffset;
+                    vertices << midPoint.x() << midPoint.y() + indicatorSize << midPoint.z() + indicatorOffset;
+                }
+            } else { // m_isSnappingVertical
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                    vertices << midPoint.x() + indicatorOffset << midPoint.y() << midPoint.z() - indicatorSize;
+                    vertices << midPoint.x() + indicatorOffset << midPoint.y() << midPoint.z() + indicatorSize;
+                } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                    vertices << midPoint.x() + indicatorOffset << midPoint.y() - indicatorSize << midPoint.z();
+                    vertices << midPoint.x() + indicatorOffset << midPoint.y() + indicatorSize << midPoint.z();
+                } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::YZ) {
+                    vertices << midPoint.x() << midPoint.y() + indicatorOffset << midPoint.z() - indicatorSize;
+                    vertices << midPoint.x() << midPoint.y() + indicatorOffset << midPoint.z() + indicatorSize;
+                }
+            }
+            m_viewport->vbo().bind();
+            m_viewport->vbo().allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
+            glDrawArrays(GL_LINES, 0, 2);
+        }
+    }
+}
+
+void LineTool::paint2D(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection)
+{
+    if (m_isDefining) {
+        QVector3D worldPos;
+        QVector3D startPos(m_firstLinePoint.X(), m_firstLinePoint.Y(), m_firstLinePoint.Z());
+        QString dimText;
+        QString angleText;
+
+        QString dimInput = m_viewport->property("dimensionInput").toString();
+        QString angleInput = m_viewport->property("angleInput").toString();
+        bool lengthFromInput = false;
+        bool angleFromInput = false;
+        double inputLength = 0;
+        double inputAngleDegrees = 0;
+        double lineLength = 0;
+
+        if (!dimInput.isEmpty()) {
+            bool ok;
+            inputLength = dimInput.toDouble(&ok);
+            if (ok) lengthFromInput = true;
+        }
+        if (!angleInput.isEmpty()) {
+            bool ok;
+            inputAngleDegrees = angleInput.toDouble(&ok);
+            if (ok) angleFromInput = true;
+        }
+
+        if (angleFromInput) {
+            QVector3D refDir;
+            if (m_viewport->property("isChainedLine").toBool()) {
+                refDir = m_viewport->property("previousLineDirection").value<QVector3D>();
+            } else {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY || m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                    refDir = QVector3D(1, 0, 0);
+                } else { // YZ
+                    refDir = QVector3D(0, 0, -1);
+                }
+            }
+
+            QVector3D currentMouseWorldPos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+            QVector3D mouseVec = currentMouseWorldPos - startPos;
+
+            double mouseAngle;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) mouseAngle = qRadiansToDegrees(atan2(mouseVec.z(), mouseVec.x()));
+            else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) mouseAngle = qRadiansToDegrees(atan2(mouseVec.y(), mouseVec.x()));
+            else mouseAngle = qRadiansToDegrees(atan2(mouseVec.z(), mouseVec.y()));
+
+            double refAngle;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) refAngle = qRadiansToDegrees(atan2(refDir.z(), refDir.x()));
+            else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) refAngle = qRadiansToDegrees(atan2(refDir.y(), refDir.x()));
+            else refAngle = qRadiansToDegrees(atan2(refDir.z(), refDir.y()));
+
+            double relativeMouseAngle = mouseAngle - refAngle;
+            while (relativeMouseAngle <= -180.0) relativeMouseAngle += 360.0;
+            while (relativeMouseAngle > 180.0) relativeMouseAngle -= 360.0;
+
+            double snappedAngle = 0;
+            if (relativeMouseAngle >= 0 && relativeMouseAngle < 90) { // Quadrant 1
+                snappedAngle = inputAngleDegrees;
+            } else if (relativeMouseAngle >= 90 && relativeMouseAngle <= 180) { // Quadrant 2
+                snappedAngle = 180.0 - inputAngleDegrees;
+            } else if (relativeMouseAngle < -90) { // Quadrant 3
+                snappedAngle = -180.0 + inputAngleDegrees;
+            } else { // Quadrant 4
+                snappedAngle = -inputAngleDegrees;
+            }
+
+            double finalAngleRad = qDegreesToRadians(refAngle + snappedAngle);
+            QVector3D finalDir;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) finalDir = QVector3D(cos(finalAngleRad), 0, sin(finalAngleRad));
+            else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) finalDir = QVector3D(cos(finalAngleRad), sin(finalAngleRad), 0);
+            else finalDir = QVector3D(0, cos(finalAngleRad), sin(finalAngleRad));
+
+            if (lengthFromInput) {
+                lineLength = inputLength;
+            } else {
+                lineLength = QVector3D::dotProduct(mouseVec, finalDir);
+                 if (lineLength < 0) lineLength = 0;
+            }
+            worldPos = startPos + lineLength * finalDir;
+
+        } else if (lengthFromInput) {
+            lineLength = inputLength;
+            QVector3D currentMouseWorldPos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+            QVector3D dir = (currentMouseWorldPos - startPos);
+            if (dir.length() > 1e-6) {
+                dir.normalize();
+                worldPos = startPos + inputLength * dir;
+            } else {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY || m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                    worldPos = startPos + QVector3D(inputLength, 0, 0);
+                } else {
+                    worldPos = startPos + QVector3D(0, inputLength, 0);
+                }
+            }
+        } else {
+            worldPos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+            if (m_viewport->isSnappingOrigin()) {
+                worldPos.setX(0); worldPos.setY(0); worldPos.setZ(0);
+            } else if (m_viewport->isSnappingVertex()) {
+                worldPos.setX(m_viewport->snapVertex().X()); worldPos.setY(m_viewport->snapVertex().Y()); worldPos.setZ(m_viewport->snapVertex().Z());
+            } else if (m_viewport->isSnappingHorizontal()) {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) worldPos.setZ(m_firstLinePoint.Z());
+                else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) worldPos.setY(m_firstLinePoint.Y());
+                else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::YZ) worldPos.setZ(m_firstLinePoint.Z());
+            } else if (m_viewport->isSnappingVertical()) {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) worldPos.setX(m_firstLinePoint.X());
+                else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) worldPos.setX(m_firstLinePoint.X());
+                else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::YZ) worldPos.setY(m_firstLinePoint.Y());
+            }
+            lineLength = (worldPos - startPos).length();
+        }
+
+        QVector3D lineVec = worldPos - startPos;
+        if (lineVec.length() > 1e-6) {
+            double refAngle, lineAngle;
+            QVector3D refDir;
+            if (m_viewport->property("isChainedLine").toBool()) {
+                refDir = m_viewport->property("previousLineDirection").value<QVector3D>();
+            } else {
+                if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY || m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) refDir = QVector3D(1, 0, 0);
+                else refDir = QVector3D(0, 0, -1);
+            }
+
+            QVector3D currentMouseWorldPosForText = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+            QVector3D mouseVecForText = currentMouseWorldPosForText - startPos;
+
+            if (angleFromInput) {
+                if (mouseVecForText.length() > 1e-6) {
+                    double mouseAngle;
+                    if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) mouseAngle = qRadiansToDegrees(atan2(mouseVecForText.z(), mouseVecForText.x()));
+                    else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) mouseAngle = qRadiansToDegrees(atan2(mouseVecForText.y(), mouseVecForText.x()));
+                    else mouseAngle = qRadiansToDegrees(atan2(mouseVecForText.z(), mouseVecForText.y()));
+
+                    double refAngleForQuadrant;
+                    if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) refAngleForQuadrant = qRadiansToDegrees(atan2(refDir.z(), refDir.x()));
+                    else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) refAngleForQuadrant = qRadiansToDegrees(atan2(refDir.y(), refDir.x()));
+                    else refAngleForQuadrant = qRadiansToDegrees(atan2(refDir.z(), refDir.y()));
+
+                    double relativeMouseAngle = mouseAngle - refAngleForQuadrant;
+                    while (relativeMouseAngle <= -180.0) relativeMouseAngle += 360.0;
+                    while (relativeMouseAngle > 180.0) relativeMouseAngle -= 360.0;
+
+                    if (relativeMouseAngle >= 90 || relativeMouseAngle < -90) {
+                        refDir = -refDir;
+                    }
+                }
+            } else {
+                if (m_viewport->property("isChainedLine").toBool()) {
+                    refDir = -refDir;
+                }
+            }
+
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                refAngle = atan2(refDir.z(), refDir.x());
+                lineAngle = atan2(lineVec.z(), lineVec.x());
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                refAngle = atan2(refDir.y(), refDir.x());
+                lineAngle = atan2(lineVec.y(), lineVec.x());
+            } else { // YZ
+                refAngle = atan2(refDir.z(), refDir.y());
+                lineAngle = atan2(lineVec.z(), lineVec.y());
+            }
+
+            double angleDiff = lineAngle - refAngle;
+            while (angleDiff <= -M_PI) angleDiff += 2 * M_PI;
+            while (angleDiff > M_PI) angleDiff -= 2 * M_PI;
+            lineAngle = refAngle + angleDiff;
+
+            QVector3D perpVec;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                perpVec = QVector3D(-lineVec.z(), 0, lineVec.x()).normalized();
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                perpVec = QVector3D(-lineVec.y(), lineVec.x(), 0).normalized();
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::YZ) {
+                perpVec = QVector3D(0, -lineVec.z(), lineVec.y()).normalized();
+            }
+
+            if (angleDiff < 0) {
+                perpVec = -perpVec;
+            }
+
+            float offset = 0.05f * -m_viewport->camera()->zoom();
+            QVector3D dimStart = startPos + offset * perpVec;
+            QVector3D dimEnd = worldPos + offset * perpVec;
+            QVector3D textPos3D = (dimStart + dimEnd) / 2.0f + 0.015f * -m_viewport->camera()->zoom() * perpVec;
+
+            QVector3D screenPos = m_viewport->project(textPos3D, modelView, projection, m_viewport->rect());
+
+            painter.setRenderHint(QPainter::Antialiasing);
+            QFontMetrics fm(painter.font());
+
+            if (screenPos.z() < 1.0f) {
+                dimText = lengthFromInput ? dimInput : QString::number(lineLength, 'f', 2);
+
+                QRect textRect = fm.boundingRect(dimText + "_");
+                textRect.moveCenter(screenPos.toPoint());
+
+                if (m_viewport->property("dimensionEditMode").toString() == "length") {
+                    painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(64, 128, 255));
+                } else {
+                    painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(50, 50, 50));
+                }
+                painter.setPen(Qt::white);
+                painter.drawText(textRect, Qt::AlignCenter, dimText);
+            }
+
+            // Angle dimension text
+            double angleDiffDegrees = qRadiansToDegrees(angleDiff);
+            while (angleDiffDegrees <= -180.0) angleDiffDegrees += 360.0;
+            while (angleDiffDegrees > 180.0) angleDiffDegrees -= 360.0;
+
+            angleText = angleFromInput ? angleInput : QString::number(qAbs(angleDiffDegrees), 'f', 1) + QChar(0x00B0);
+
+            const float radius = 0.1f * -m_viewport->camera()->zoom();
+            double midAngle = refAngle + (lineAngle - refAngle) / 2.0;
+            QVector3D textPos3DAngle;
+            float textOffset = 0.035f * -m_viewport->camera()->zoom();
+
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) textPos3DAngle = startPos + (radius + textOffset) * QVector3D(cos(midAngle), 0, sin(midAngle));
+            else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) textPos3DAngle = startPos + (radius + textOffset) * QVector3D(cos(midAngle), sin(midAngle), 0);
+            else textPos3DAngle = startPos + (radius + textOffset) * QVector3D(0, cos(midAngle), sin(midAngle));
+
+            QVector3D screenPosAngle = m_viewport->project(textPos3DAngle, modelView, projection, m_viewport->rect());
+            if (screenPosAngle.z() < 1.0f) {
+                QRect angleTextRect = fm.boundingRect(angleText + "_");
+                angleTextRect.moveCenter(screenPosAngle.toPoint());
+                if (m_viewport->property("dimensionEditMode").toString() == "angle") {
+                    painter.fillRect(angleTextRect.adjusted(-4, -2, 4, 2), QColor(64, 128, 255));
+                } else {
+                    painter.fillRect(angleTextRect.adjusted(-4, -2, 4, 2), QColor(50, 50, 50));
+                }
+                painter.setPen(Qt::white);
+                painter.drawText(angleTextRect, Qt::AlignCenter, angleText);
+            }
+        }
+    }
+}

src/LineTool.h

@@ -0,0 +1,28 @@
+#ifndef LINETOOL_H
+#define LINETOOL_H
+
+#include "SketchTool.h"
+#include <gp_Pnt.hxx>
+
+class LineTool : public SketchTool
+{
+    Q_OBJECT
+public:
+    explicit LineTool(ViewportWidget* viewport);
+
+    void mousePressEvent(QMouseEvent *event) override;
+    void mouseMoveEvent(QMouseEvent *event) override;
+
+    void paintGL() override;
+    void paint2D(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection) override;
+
+    void activate() override;
+
+protected:
+    void finalizeCreation() override;
+
+private:
+    gp_Pnt m_firstLinePoint;
+};
+
+#endif // LINETOOL_H

src/MainWindow.cpp

@@ -17,11 +17,14 @@
 #include <QIcon>
 #include <QInputDialog>
 #include <QStringList>
+#include <QKeyEvent>
+#include <QApplication>
 
 MainWindow::MainWindow(ApplicationController* appController, QWidget *parent)
     : QMainWindow(parent)
     , m_appController(appController)
 {
+    qApp->installEventFilter(this);
     setWindowTitle("OpenCAD");
     resize(1920, 1080);
 
@@ -143,6 +146,8 @@ MainWindow::MainWindow(ApplicationController* appController, QWidget *parent)
     connect(m_appController, &ApplicationController::planeSelectionModeStarted, m_viewport, &ViewportWidget::onPlaneSelectionModeStarted);
 
     connect(m_viewport, &ViewportWidget::lineAdded, m_appController, &ApplicationController::addLine);
+    connect(m_viewport, &ViewportWidget::rectangleAdded, m_appController, &ApplicationController::addRectangle);
+    connect(m_viewport, &ViewportWidget::circleAdded, m_appController, &ApplicationController::addCircle);
     connect(m_viewport, &ViewportWidget::planeSelected, m_appController, &ApplicationController::onPlaneSelected);
     connect(m_viewport, &ViewportWidget::toolDeactivated, m_appController, [this]() { m_appController->setActiveTool(ApplicationController::ToolType::None); });
 
@@ -204,3 +209,19 @@ void MainWindow::updateWindowTitle(const QString& filePath)
         shownName = "Untitled";
     setWindowTitle(tr("%1[*] - %2").arg(QFileInfo(shownName).fileName(), tr("OpenCAD")));
 }
+
+bool MainWindow::eventFilter(QObject *watched, QEvent *event)
+{
+    if (m_appController->activeTool() != ApplicationController::ToolType::None && event->type() == QEvent::KeyPress) {
+        QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
+        if (keyEvent->key() == Qt::Key_Tab || keyEvent->key() == Qt::Key_Backtab) {
+            if (watched == m_viewport) {
+                return false; // Let the viewport handle its own event
+            }
+            // Forward event to viewport and consume it
+            QApplication::sendEvent(m_viewport, keyEvent);
+            return true;
+        }
+    }
+    return QMainWindow::eventFilter(watched, event);
+}

src/MainWindow.h

@@ -3,6 +3,7 @@
 
 #include <QMainWindow>
 
+class QEvent;
 class ViewportWidget;
 class Document;
 class Feature;
@@ -29,6 +30,9 @@ private slots:
     void exitSketchMode();
     void updateWindowTitle(const QString& filePath);
 
+protected:
+    bool eventFilter(QObject *watched, QEvent *event) override;
+
 private:
     ApplicationController* m_appController;
     ViewportWidget *m_viewport;

src/RectangleTool.cpp

@@ -0,0 +1,392 @@
+#include "RectangleTool.h"
+#include "ViewportWidget.h"
+#include "Camera.h"
+#include <QMouseEvent>
+#include <QKeyEvent>
+#include <QPainter>
+#include <QVector>
+#include <QOpenGLShaderProgram>
+#include <cmath>
+#include <QtMath>
+
+RectangleTool::RectangleTool(ViewportWidget* viewport)
+    : SketchTool(viewport)
+{
+}
+
+void RectangleTool::activate()
+{
+    SketchTool::activate();
+    m_dimensionModes << "height" << "width";
+    m_dimensionPropertyNames["height"] = "heightInput";
+    m_dimensionPropertyNames["width"] = "widthInput";
+
+    m_viewport->setProperty("widthInput", "");
+    m_viewport->setProperty("heightInput", "");
+    m_viewport->setProperty("dimensionEditMode", "height");
+}
+
+void RectangleTool::mousePressEvent(QMouseEvent *event)
+{
+    gp_Pnt p;
+    if (!m_isDefining) {
+        if (m_viewport->isSnappingOrigin()) {
+            p.SetCoord(0, 0, 0);
+        } else if (m_viewport->isSnappingVertex()) {
+            p = m_viewport->snapVertex();
+        } else {
+            QVector3D worldPos = m_viewport->unproject(event->pos(), m_viewport->currentPlane());
+            p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+        }
+        m_firstRectanglePoint = p;
+        m_isDefining = true;
+        m_viewport->setProperty("widthInput", "");
+        m_viewport->setProperty("heightInput", "");
+        m_viewport->setProperty("dimensionEditMode", "height");
+    } else {
+        QVector3D worldPos;
+        QVector3D startPos(m_firstRectanglePoint.X(), m_firstRectanglePoint.Y(), m_firstRectanglePoint.Z());
+
+        QString widthInput = m_viewport->property("widthInput").toString();
+        QString heightInput = m_viewport->property("heightInput").toString();
+        bool widthFromInput = false, heightFromInput = false;
+        double inputWidth = 0, inputHeight = 0;
+
+        if (!widthInput.isEmpty()) {
+            bool ok;
+            inputWidth = widthInput.toDouble(&ok);
+            if (ok) widthFromInput = true;
+        }
+        if (!heightInput.isEmpty()) {
+            bool ok;
+            inputHeight = heightInput.toDouble(&ok);
+            if (ok) heightFromInput = true;
+        }
+
+        if (widthFromInput || heightFromInput) {
+            QVector3D mousePos = m_viewport->unproject(event->pos(), m_viewport->currentPlane());
+            QVector3D mouseDir = mousePos - startPos;
+            double current_w, current_h;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                current_w = qAbs(mouseDir.x());
+                current_h = qAbs(mouseDir.z());
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                current_w = qAbs(mouseDir.x());
+                current_h = qAbs(mouseDir.y());
+            } else { // YZ
+                current_w = qAbs(mouseDir.y());
+                current_h = qAbs(mouseDir.z());
+            }
+            double rect_w = widthFromInput ? inputWidth : current_w;
+            double rect_h = heightFromInput ? inputHeight : current_h;
+            int signX = (mouseDir.x() >= 0) ? 1 : -1;
+            int signY = (mouseDir.y() >= 0) ? 1 : -1;
+            int signZ = (mouseDir.z() >= 0) ? 1 : -1;
+            worldPos = startPos;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                worldPos.setX(startPos.x() + signX * rect_w);
+                worldPos.setZ(startPos.z() + signZ * rect_h);
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                worldPos.setX(startPos.x() + signX * rect_w);
+                worldPos.setY(startPos.y() + signY * rect_h);
+            } else { // YZ
+                worldPos.setY(startPos.y() + signY * rect_w);
+                worldPos.setZ(startPos.z() + signZ * rect_h);
+            }
+        } else {
+            if (m_viewport->isSnappingOrigin()) {
+                worldPos.setX(0); worldPos.setY(0); worldPos.setZ(0);
+            } else if (m_viewport->isSnappingVertex()) {
+                worldPos = QVector3D(m_viewport->snapVertex().X(), m_viewport->snapVertex().Y(), m_viewport->snapVertex().Z());
+            } else {
+                worldPos = m_viewport->unproject(event->pos(), m_viewport->currentPlane());
+            }
+        }
+        p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+        emit m_viewport->rectangleAdded(m_firstRectanglePoint, p);
+        deactivate();
+    }
+}
+
+void RectangleTool::mouseMoveEvent(QMouseEvent *event)
+{
+    // To be implemented
+}
+
+void RectangleTool::finalizeCreation()
+{
+    QVector3D worldPos;
+    QVector3D startPos(m_firstRectanglePoint.X(), m_firstRectanglePoint.Y(), m_firstRectanglePoint.Z());
+
+    QString widthInput = m_viewport->property("widthInput").toString();
+    QString heightInput = m_viewport->property("heightInput").toString();
+    bool widthFromInput = false, heightFromInput = false;
+    double inputWidth = 0, inputHeight = 0;
+
+    if (!widthInput.isEmpty()) {
+        bool ok;
+        inputWidth = widthInput.toDouble(&ok);
+        if (ok) widthFromInput = true;
+    }
+    if (!heightInput.isEmpty()) {
+        bool ok;
+        inputHeight = heightInput.toDouble(&ok);
+        if (ok) heightFromInput = true;
+    }
+
+    if (widthFromInput || heightFromInput) {
+        QVector3D mousePos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+        QVector3D mouseDir = mousePos - startPos;
+        double current_w, current_h;
+        if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+            current_w = qAbs(mouseDir.x());
+            current_h = qAbs(mouseDir.z());
+        } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+            current_w = qAbs(mouseDir.x());
+            current_h = qAbs(mouseDir.y());
+        } else { // YZ
+            current_w = qAbs(mouseDir.y());
+            current_h = qAbs(mouseDir.z());
+        }
+        double rect_w = widthFromInput ? inputWidth : current_w;
+        double rect_h = heightFromInput ? inputHeight : current_h;
+        int signX = (mouseDir.x() >= 0) ? 1 : -1;
+        int signY = (mouseDir.y() >= 0) ? 1 : -1;
+        int signZ = (mouseDir.z() >= 0) ? 1 : -1;
+        worldPos = startPos;
+        if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+            worldPos.setX(startPos.x() + signX * rect_w);
+            worldPos.setZ(startPos.z() + signZ * rect_h);
+        } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+            worldPos.setX(startPos.x() + signX * rect_w);
+            worldPos.setY(startPos.y() + signY * rect_h);
+        } else { // YZ
+            worldPos.setY(startPos.y() + signY * rect_w);
+            worldPos.setZ(startPos.z() + signZ * rect_h);
+        }
+    } else {
+        worldPos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+    }
+
+    gp_Pnt p;
+    p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+
+    emit m_viewport->rectangleAdded(m_firstRectanglePoint, p);
+    deactivate();
+}
+
+void RectangleTool::paintGL()
+{
+    if (m_isDefining) {
+        QVector<GLfloat> vertices;
+        QVector3D worldPos;
+        QVector3D startPos(m_firstRectanglePoint.X(), m_firstRectanglePoint.Y(), m_firstRectanglePoint.Z());
+
+        QString widthInput = m_viewport->property("widthInput").toString();
+        QString heightInput = m_viewport->property("heightInput").toString();
+        bool widthFromInput = false;
+        bool heightFromInput = false;
+        double inputWidth = 0, inputHeight = 0;
+
+        if (!widthInput.isEmpty()) {
+            bool ok;
+            inputWidth = widthInput.toDouble(&ok);
+            if (ok) widthFromInput = true;
+        }
+        if (!heightInput.isEmpty()) {
+            bool ok;
+            inputHeight = heightInput.toDouble(&ok);
+            if (ok) heightFromInput = true;
+        }
+
+        QVector3D mousePos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+
+        if (widthFromInput || heightFromInput) {
+            QVector3D mouseDir = mousePos - startPos;
+            double current_w, current_h;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                current_w = qAbs(mouseDir.x());
+                current_h = qAbs(mouseDir.z());
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                current_w = qAbs(mouseDir.x());
+                current_h = qAbs(mouseDir.y());
+            } else { // YZ
+                current_w = qAbs(mouseDir.y());
+                current_h = qAbs(mouseDir.z());
+            }
+            double rect_w = widthFromInput ? inputWidth : current_w;
+            double rect_h = heightFromInput ? inputHeight : current_h;
+            int signX = (mouseDir.x() >= 0) ? 1 : -1;
+            int signY = (mouseDir.y() >= 0) ? 1 : -1;
+            int signZ = (mouseDir.z() >= 0) ? 1 : -1;
+            worldPos = startPos;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                worldPos.setX(startPos.x() + signX * rect_w);
+                worldPos.setZ(startPos.z() + signZ * rect_h);
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                worldPos.setX(startPos.x() + signX * rect_w);
+                worldPos.setY(startPos.y() + signY * rect_h);
+            } else { // YZ
+                worldPos.setY(startPos.y() + signY * rect_w);
+                worldPos.setZ(startPos.z() + signZ * rect_h);
+            }
+        } else {
+            worldPos = mousePos;
+            if (m_viewport->isSnappingOrigin()) {
+                worldPos.setX(0); worldPos.setY(0); worldPos.setZ(0);
+            } else if (m_viewport->isSnappingVertex()) {
+                worldPos.setX(m_viewport->snapVertex().X()); worldPos.setY(m_viewport->snapVertex().Y()); worldPos.setZ(m_viewport->snapVertex().Z());
+            }
+        }
+
+        QVector3D p1 = startPos;
+        QVector3D p2, p3, p4;
+        p3 = worldPos;
+
+        if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+            p2.setX(p3.x()); p2.setY(p1.y()); p2.setZ(p1.z());
+            p4.setX(p1.x()); p4.setY(p1.y()); p4.setZ(p3.z());
+        } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+            p2.setX(p3.x()); p2.setY(p1.y()); p2.setZ(p1.z());
+            p4.setX(p1.x()); p4.setY(p3.y()); p4.setZ(p1.z());
+        } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::YZ) {
+            p2.setX(p1.x()); p2.setY(p3.y()); p2.setZ(p1.z());
+            p4.setX(p1.x()); p4.setY(p1.y()); p4.setZ(p3.z());
+        }
+
+        vertices << p1.x() << p1.y() << p1.z();
+        vertices << p2.x() << p2.y() << p2.z();
+        vertices << p2.x() << p2.y() << p2.z();
+        vertices << p3.x() << p3.y() << p3.z();
+        vertices << p3.x() << p3.y() << p3.z();
+        vertices << p4.x() << p4.y() << p4.z();
+        vertices << p4.x() << p4.y() << p4.z();
+        vertices << p1.x() << p1.y() << p1.z();
+
+        m_viewport->shaderProgram()->setUniformValue(m_viewport->colorLoc(), QVector4D(1.0f, 1.0f, 0.0f, 1.0f));
+        m_viewport->vbo().bind();
+        m_viewport->vbo().allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
+        glDrawArrays(GL_LINES, 0, 8);
+    }
+}
+
+void RectangleTool::paint2D(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection)
+{
+    if (m_isDefining) {
+        QVector3D worldPos;
+        QVector3D p1_3d(m_firstRectanglePoint.X(), m_firstRectanglePoint.Y(), m_firstRectanglePoint.Z());
+
+        QString widthInput = m_viewport->property("widthInput").toString();
+        QString heightInput = m_viewport->property("heightInput").toString();
+        bool widthFromInput = false;
+        bool heightFromInput = false;
+        double inputWidth = 0, inputHeight = 0;
+
+        if (!widthInput.isEmpty()) {
+            bool ok;
+            inputWidth = widthInput.toDouble(&ok);
+            if (ok) widthFromInput = true;
+        }
+        if (!heightInput.isEmpty()) {
+            bool ok;
+            inputHeight = heightInput.toDouble(&ok);
+            if (ok) heightFromInput = true;
+        }
+
+        QVector3D mousePos = m_viewport->unproject(m_viewport->currentMousePos(), m_viewport->currentPlane());
+
+        if (widthFromInput || heightFromInput) {
+            QVector3D mouseDir = mousePos - p1_3d;
+            double current_w, current_h;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                current_w = qAbs(mouseDir.x());
+                current_h = qAbs(mouseDir.z());
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                current_w = qAbs(mouseDir.x());
+                current_h = qAbs(mouseDir.y());
+            } else { // YZ
+                current_w = qAbs(mouseDir.y());
+                current_h = qAbs(mouseDir.z());
+            }
+            double rect_w = widthFromInput ? inputWidth : current_w;
+            double rect_h = heightFromInput ? inputHeight : current_h;
+            int signX = (mouseDir.x() >= 0) ? 1 : -1;
+            int signY = (mouseDir.y() >= 0) ? 1 : -1;
+            int signZ = (mouseDir.z() >= 0) ? 1 : -1;
+            worldPos = p1_3d;
+            if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+                worldPos.setX(p1_3d.x() + signX * rect_w);
+                worldPos.setZ(p1_3d.z() + signZ * rect_h);
+            } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+                worldPos.setX(p1_3d.x() + signX * rect_w);
+                worldPos.setY(p1_3d.y() + signY * rect_h);
+            } else { // YZ
+                worldPos.setY(p1_3d.y() + signY * rect_w);
+                worldPos.setZ(p1_3d.z() + signZ * rect_h);
+            }
+        } else {
+            worldPos = mousePos;
+            if (m_viewport->isSnappingOrigin()) {
+                worldPos.setX(0); worldPos.setY(0); worldPos.setZ(0);
+            } else if (m_viewport->isSnappingVertex()) {
+                worldPos.setX(m_viewport->snapVertex().X()); worldPos.setY(m_viewport->snapVertex().Y()); worldPos.setZ(m_viewport->snapVertex().Z());
+            }
+        }
+        QVector3D p3_3d = worldPos;
+        QVector3D p2_3d, p4_3d;
+
+        double w, h;
+
+        if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+            p2_3d.setX(p3_3d.x()); p2_3d.setY(p1_3d.y()); p2_3d.setZ(p1_3d.z());
+            p4_3d.setX(p1_3d.x()); p4_3d.setY(p1_3d.y()); p4_3d.setZ(p3_3d.z());
+            w = qAbs(p3_3d.x() - p1_3d.x());
+            h = qAbs(p3_3d.z() - p1_3d.z());
+        } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+            p2_3d.setX(p3_3d.x()); p2_3d.setY(p1_3d.y()); p2_3d.setZ(p1_3d.z());
+            p4_3d.setX(p1_3d.x()); p4_3d.setY(p3_3d.y()); p4_3d.setZ(p1_3d.z());
+            w = qAbs(p3_3d.x() - p1_3d.x());
+            h = qAbs(p3_3d.y() - p1_3d.y());
+        } else { // YZ
+            p2_3d.setX(p1_3d.x()); p2_3d.setY(p3_3d.y()); p2_3d.setZ(p1_3d.z());
+            p4_3d.setX(p1_3d.x()); p4_3d.setY(p1_3d.y()); p4_3d.setZ(p3_3d.z());
+            w = qAbs(p3_3d.y() - p1_3d.y());
+            h = qAbs(p3_3d.z() - p1_3d.z());
+        }
+
+        painter.setRenderHint(QPainter::Antialiasing);
+        QFontMetrics fm(painter.font());
+
+        // Width dimension
+        QVector3D widthTextPos3D = (p1_3d + p2_3d) / 2.0f;
+        QVector3D screenPosW = m_viewport->project(widthTextPos3D, modelView, projection, m_viewport->rect());
+        if (screenPosW.z() < 1.0f) {
+            QString widthText = widthFromInput ? widthInput : QString::number(w, 'f', 2);
+            QRect textRect = fm.boundingRect(widthText + "__");
+            textRect.moveCenter(screenPosW.toPoint() + QPoint(0, (p3_3d.z() > p1_3d.z() || p3_3d.y() > p1_3d.y()) ? -15 : 15));
+            if (m_viewport->property("dimensionEditMode").toString() == "width") {
+                painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(64, 128, 255));
+            } else {
+                painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(50, 50, 50));
+            }
+            painter.setPen(Qt::white);
+            painter.drawText(textRect, Qt::AlignCenter, widthText);
+        }
+
+        // Height dimension
+        QVector3D heightTextPos3D = (p2_3d + p3_3d) / 2.0f;
+        QVector3D screenPosH = m_viewport->project(heightTextPos3D, modelView, projection, m_viewport->rect());
+        if (screenPosH.z() < 1.0f) {
+            QString heightText = heightFromInput ? heightInput : QString::number(h, 'f', 2);
+            QRect textRect = fm.boundingRect(heightText + "__");
+            textRect.moveCenter(screenPosH.toPoint() + QPoint((p3_3d.x() > p1_3d.x()) ? 15 : -15, 0));
+            if (m_viewport->property("dimensionEditMode").toString() == "height") {
+                painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(64, 128, 255));
+            } else {
+                painter.fillRect(textRect.adjusted(-4, -2, 4, 2), QColor(50, 50, 50));
+            }
+            painter.setPen(Qt::white);
+            painter.drawText(textRect, Qt::AlignCenter, heightText);
+        }
+    }
+}

src/RectangleTool.h

@@ -0,0 +1,28 @@
+#ifndef RECTANGLETOOL_H
+#define RECTANGLETOOL_H
+
+#include "SketchTool.h"
+#include <gp_Pnt.hxx>
+
+class RectangleTool : public SketchTool
+{
+    Q_OBJECT
+public:
+    explicit RectangleTool(ViewportWidget* viewport);
+
+    void mousePressEvent(QMouseEvent *event) override;
+    void mouseMoveEvent(QMouseEvent *event) override;
+
+    void paintGL() override;
+    void paint2D(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection) override;
+
+    void activate() override;
+
+protected:
+    void finalizeCreation() override;
+
+private:
+    gp_Pnt m_firstRectanglePoint;
+};
+
+#endif // RECTANGLETOOL_H

src/SketchCircle.cpp

@@ -0,0 +1,56 @@
+#include "SketchCircle.h"
+#include <QJsonArray>
+
+namespace
+{
+    void pointToJson(const gp_Pnt& p, QJsonArray& arr)
+    {
+        arr.append(p.X());
+        arr.append(p.Y());
+        arr.append(p.Z());
+    }
+
+    gp_Pnt jsonToPoint(const QJsonArray& arr)
+    {
+        return gp_Pnt(arr[0].toDouble(), arr[1].toDouble(), arr[2].toDouble());
+    }
+}
+
+SketchCircle::SketchCircle() : m_radius(0.0)
+{
+}
+
+SketchCircle::SketchCircle(const gp_Pnt& center, double radius)
+    : m_center(center), m_radius(radius)
+{
+}
+
+SketchObject::ObjectType SketchCircle::type() const
+{
+    return ObjectType::Circle;
+}
+
+void SketchCircle::read(const QJsonObject& json)
+{
+    m_center = jsonToPoint(json["center"].toArray());
+    m_radius = json["radius"].toDouble();
+}
+
+void SketchCircle::write(QJsonObject& json) const
+{
+    QJsonArray centerArr;
+    pointToJson(m_center, centerArr);
+    json["center"] = centerArr;
+    json["radius"] = m_radius;
+    json["type"] = "Circle";
+}
+
+const gp_Pnt& SketchCircle::center() const
+{
+    return m_center;
+}
+
+double SketchCircle::radius() const
+{
+    return m_radius;
+}

src/SketchCircle.h

@@ -0,0 +1,26 @@
+#ifndef SKETCHCIRCLE_H
+#define SKETCHCIRCLE_H
+
+#include "SketchObject.h"
+#include <gp_Pnt.hxx>
+
+class SketchCircle : public SketchObject
+{
+public:
+    SketchCircle();
+    SketchCircle(const gp_Pnt& center, double radius);
+
+    ObjectType type() const override;
+
+    void read(const QJsonObject& json) override;
+    void write(QJsonObject& json) const override;
+
+    const gp_Pnt& center() const;
+    double radius() const;
+
+private:
+    gp_Pnt m_center;
+    double m_radius;
+};
+
+#endif // SKETCHCIRCLE_H

src/SketchFeature.cpp

@@ -1,8 +1,25 @@
 #include "SketchFeature.h"
 #include "SketchObject.h"
 #include "SketchLine.h"
+#include "SketchRectangle.h"
+#include "SketchCircle.h"
+
+#include <BRepBuilderAPI_MakeEdge.hxx>
+#include <BRepBuilderAPI_MakeWire.hxx>
+#include <BRepBuilderAPI_MakeFace.hxx>
+#include <BRep_Builder.hxx>
+#include <TopoDS_Compound.hxx>
+#include <TopoDS.hxx>
+#include <gp_Circ.hxx>
+#include <gp_Ax2.hxx>
+#include <TopExp_Explorer.hxx>
+#include <ShapeAnalysis_FreeBounds.hxx>
+#include <gp_Pln.hxx>
+#include <BRepOffsetAPI_MakeFilling.hxx>
+#include <GeomAbs_Shape.hxx>
 
 #include <QJsonArray>
+#include <QDebug>
 
 SketchFeature::SketchFeature(const QString& name)
     : Feature(name)
@@ -34,6 +51,119 @@ const TopoDS_Shape& SketchFeature::shape() const
     return m_shape;
 }
 
+void SketchFeature::buildShape()
+{
+    m_shape.Nullify();
+    QList<TopoDS_Edge> lineEdges;
+    QList<TopoDS_Face> faces;
+
+    gp_Pln sketchPlane;
+    switch (m_plane) {
+        case SketchPlane::XY: sketchPlane = gp_Pln(gp::Origin(), gp::DY()); break;
+        case SketchPlane::XZ: sketchPlane = gp_Pln(gp::Origin(), gp::DZ()); break;
+        case SketchPlane::YZ: sketchPlane = gp_Pln(gp::Origin(), gp::DX()); break;
+    }
+
+    for (SketchObject* obj : m_objects) {
+        if (auto line = dynamic_cast<SketchLine*>(obj)) {
+            BRepBuilderAPI_MakeEdge makeEdge(line->startPoint(), line->endPoint());
+            if (makeEdge.IsDone()) {
+                lineEdges.append(makeEdge.Edge());
+            }
+        } else if (auto rect = dynamic_cast<SketchRectangle*>(obj)) {
+            const gp_Pnt& c1 = rect->corner1();
+            const gp_Pnt& c2 = rect->corner2();
+            gp_Pnt other_corner1, other_corner2;
+
+            if (m_plane == SketchPlane::XY) {
+                other_corner1.SetCoord(c2.X(), c1.Y(), c1.Z());
+                other_corner2.SetCoord(c1.X(), c1.Y(), c2.Z());
+            } else if (m_plane == SketchPlane::XZ) {
+                other_corner1.SetCoord(c2.X(), c1.Y(), c1.Z());
+                other_corner2.SetCoord(c1.X(), c2.Y(), c1.Z());
+            } else { // YZ
+                other_corner1.SetCoord(c1.X(), c2.Y(), c1.Z());
+                other_corner2.SetCoord(c1.X(), c1.Y(), c2.Z());
+            }
+
+            BRepBuilderAPI_MakeEdge me1(c1, other_corner1);
+            BRepBuilderAPI_MakeEdge me2(other_corner1, c2);
+            BRepBuilderAPI_MakeEdge me3(c2, other_corner2);
+            BRepBuilderAPI_MakeEdge me4(other_corner2, c1);
+            if (me1.IsDone() && me2.IsDone() && me3.IsDone() && me4.IsDone()) {
+                BRepBuilderAPI_MakeWire wireBuilder(me1.Edge(), me2.Edge(), me3.Edge(), me4.Edge());
+                if (wireBuilder.IsDone()) {
+                    BRepBuilderAPI_MakeFace faceBuilder(sketchPlane, wireBuilder.Wire());
+                    if (faceBuilder.IsDone()) {
+                        faces.append(faceBuilder.Face());
+                    }
+                }
+            }
+        } else if (auto circle = dynamic_cast<SketchCircle*>(obj)) {
+            const gp_Pnt& center = circle->center();
+            double radius = circle->radius();
+            gp_Dir normal;
+            switch (m_plane) {
+                case SketchPlane::XY: normal = gp::DY(); break;
+                case SketchPlane::XZ: normal = gp::DZ(); break;
+                case SketchPlane::YZ: normal = gp::DX(); break;
+            }
+            gp_Ax2 axis(center, normal);
+            gp_Circ circ(axis, radius);
+            BRepBuilderAPI_MakeEdge makeEdge(circ);
+            if (makeEdge.IsDone()) {
+                TopoDS_Edge edge = makeEdge.Edge();
+                BRepBuilderAPI_MakeWire wireBuilder(edge);
+                if(wireBuilder.IsDone()) {
+                    BRepBuilderAPI_MakeFace faceBuilder(sketchPlane, wireBuilder.Wire());
+                    if (faceBuilder.IsDone()) {
+                        faces.append(faceBuilder.Face());
+                    }
+                }
+            }
+        }
+    }
+
+    if (!lineEdges.isEmpty()) {
+        qDebug() << "buildShape: processing" << lineEdges.size() << "line edges";
+
+        BRepOffsetAPI_MakeFilling faceMaker;
+        for (const TopoDS_Edge& edge : lineEdges) {
+            faceMaker.Add(edge, GeomAbs_C0);
+        }
+        faceMaker.Build();
+
+        if (faceMaker.IsDone()) {
+            TopExp_Explorer explorer(faceMaker.Shape(), TopAbs_FACE);
+            int facesAdded = 0;
+            for (; explorer.More(); explorer.Next()) {
+                faces.append(TopoDS::Face(explorer.Current()));
+                facesAdded++;
+            }
+            qDebug() << "buildShape: added" << facesAdded << "face(s) using MakeFilling";
+        } else {
+            qDebug() << "buildShape: MakeFilling failed";
+        }
+    }
+
+    qDebug() << "buildShape: total faces created:" << faces.size();
+    if (faces.isEmpty()) {
+        return;
+    }
+
+    if (faces.size() == 1) {
+        m_shape = faces.first();
+    } else {
+        TopoDS_Compound compound;
+        BRep_Builder builder;
+        builder.MakeCompound(compound);
+        for (const auto& face : faces) {
+            builder.Add(compound, face);
+        }
+        m_shape = compound;
+    }
+}
+
 void SketchFeature::addObject(SketchObject* object)
 {
     m_objects.append(object);
@@ -66,6 +196,10 @@ void SketchFeature::read(const QJsonObject& json)
                     auto line = new SketchLine();
                     line->read(objectJson);
                     m_objects.append(line);
+                } else if (type == "Rectangle") {
+                    auto rect = new SketchRectangle();
+                    rect->read(objectJson);
+                    m_objects.append(rect);
                 }
             }
         }

src/SketchFeature.h

@@ -26,6 +26,8 @@ public:
 
     const TopoDS_Shape& shape() const;
 
+    void buildShape();
+
     void addObject(SketchObject* object);
     const QList<SketchObject*>& objects() const;
 

src/SketchGrid.cpp

@@ -1,10 +1,36 @@
 #include "SketchGrid.h"
+#include "ViewportWidget.h"
+#include "Camera.h"
 #include <QOpenGLContext>
 #include <QOpenGLExtraFunctions>
 #include <QOpenGLShaderProgram>
+#include <QPainter>
 #include <QVector>
 
-SketchGrid::SketchGrid()
+namespace {
+struct GridParams {
+    float minorIncrement;
+    float majorIncrement;
+    int gridSize;
+};
+
+GridParams getGridParams(float distance)
+{
+    if (distance > 500.0f) {
+        return { 20.0f, 100.0f, 1000 };
+    } else if (distance > 250.0f) {
+        return { 10.0f, 50.0f, 1000 };
+    } else if (distance > 50.0f) {
+        return { 5.0f, 25.0f, 1000 };
+    } else if (distance > 10.0f) {
+        return { 1.0f, 5.0f, 1000 };
+    } else { // zoomed in
+        return { 0.2f, 1.0f, 1000 };
+    }
+}
+} // namespace
+
+SketchGrid::SketchGrid(ViewportWidget* viewport) : m_viewport(viewport)
 {
 }
 
@@ -46,45 +72,51 @@ void SketchGrid::paintGL(SketchPlane plane, QOpenGLShaderProgram* shaderProgram,
 
 void SketchGrid::drawGridLines(SketchPlane plane, QOpenGLShaderProgram* shaderProgram, int colorLoc)
 {
-    const int gridSize = 50;
-    const float darkFactor = 0.8f;
-    QVector<GLfloat> lightLines;
-    QVector<GLfloat> darkLines;
+    auto params = getGridParams(-m_viewport->camera()->uiCameraDistance());
+    const float minorIncrement = params.minorIncrement;
+    const int gridSize = params.gridSize;
 
-    for (int i = -gridSize; i <= gridSize; ++i)
-    {
-        if (i == 0) continue;
-        QVector<GLfloat>& current_vector = (i % 5 == 0) ? darkLines : lightLines;
+    QVector<GLfloat> minorLines;
+    QVector<GLfloat> majorLines;
+
+    int numLines = gridSize / minorIncrement;
+    for (int i = -numLines; i <= numLines; ++i) {
+        if (i == 0)
+            continue;
+
+        float pos = i * minorIncrement;
+        QVector<GLfloat>& current_vector = (i % 5 == 0) ? majorLines : minorLines;
         if (plane == XY) {
-            current_vector << i << 0 << -gridSize << i << 0 << gridSize;
-            current_vector << -gridSize << 0 << i << gridSize << 0 << i;
+            current_vector << pos << 0 << -gridSize << pos << 0 << gridSize;
+            current_vector << -gridSize << 0 << pos << gridSize << 0 << pos;
         } else if (plane == XZ) {
-            current_vector << i << -gridSize << 0 << i << gridSize << 0;
-            current_vector << -gridSize << i << 0 << gridSize << i << 0;
+            current_vector << pos << -gridSize << 0 << pos << gridSize << 0;
+            current_vector << -gridSize << pos << 0 << gridSize << pos << 0;
         } else { // YZ
-            current_vector << 0 << i << -gridSize << 0 << i << gridSize;
-            current_vector << 0 << -gridSize << i << 0 << gridSize << i;
+            current_vector << 0 << pos << -gridSize << 0 << pos << gridSize;
+            current_vector << 0 << -gridSize << pos << 0 << gridSize << pos;
         }
     }
 
     m_vbo.bind();
 
-    // Draw lighter lines
-    shaderProgram->setUniformValue(colorLoc, QVector4D(0.5f, 0.5f, 0.5f, 1.0f));
+    // Draw minor lines
+    shaderProgram->setUniformValue(colorLoc, QVector4D(0.4f, 0.4f, 0.4f, 1.0f));
     glLineWidth(1.0f);
-    m_vbo.allocate(lightLines.constData(), lightLines.size() * sizeof(GLfloat));
-    glDrawArrays(GL_LINES, 0, lightLines.size() / 3);
+    m_vbo.allocate(minorLines.constData(), minorLines.size() * sizeof(GLfloat));
+    glDrawArrays(GL_LINES, 0, minorLines.size() / 3);
 
-    // Draw darker lines
-    shaderProgram->setUniformValue(colorLoc, QVector4D(0.5f * darkFactor, 0.5f * darkFactor, 0.5f * darkFactor, 1.0f));
-    glLineWidth(1.5f);
-    m_vbo.allocate(darkLines.constData(), darkLines.size() * sizeof(GLfloat));
-    glDrawArrays(GL_LINES, 0, darkLines.size() / 3);
+    // Draw major lines
+    shaderProgram->setUniformValue(colorLoc, QVector4D(0.6f, 0.6f, 0.6f, 1.0f));
+    glLineWidth(1.0f);
+    m_vbo.allocate(majorLines.constData(), majorLines.size() * sizeof(GLfloat));
+    glDrawArrays(GL_LINES, 0, majorLines.size() / 3);
 }
 
 void SketchGrid::drawAxes(SketchPlane plane, QOpenGLShaderProgram* shaderProgram, int colorLoc)
 {
-    const int axisLength = 50;
+    auto params = getGridParams(-m_viewport->camera()->uiCameraDistance());
+    const int axisLength = params.gridSize;
     QVector<GLfloat> vertices;
 
     glLineWidth(2.0f);
@@ -123,3 +155,41 @@ void SketchGrid::drawAxes(SketchPlane plane, QOpenGLShaderProgram* shaderProgram
     m_vbo.allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
     glDrawArrays(GL_POINTS, 0, 1);
 }
+
+void SketchGrid::paintAxisLabels(QPainter& painter, SketchGrid::SketchPlane plane, const QMatrix4x4& modelView, const QMatrix4x4& projection)
+{
+    painter.setPen(Qt::white);
+    painter.setFont(QFont("Arial", 10));
+
+    auto params = getGridParams(-m_viewport->camera()->uiCameraDistance());
+    const float majorIncrement = params.majorIncrement;
+    const int range = params.gridSize;
+
+    auto drawLabelsForAxis = [&](int axis_idx) {
+        int numLabels = range / majorIncrement;
+        for (int i = -numLabels; i <= numLabels; ++i) {
+            if (i == 0)
+                continue;
+
+            float val = i * majorIncrement;
+            QVector3D worldCoord;
+            worldCoord[axis_idx] = val;
+
+            QVector3D screenPos = m_viewport->project(worldCoord, modelView, projection, m_viewport->rect());
+            if (screenPos.z() < 1.0f) { // Not clipped
+                painter.drawText(screenPos.toPoint(), QString::number(val));
+            }
+        }
+    };
+
+    if (plane == SketchGrid::XY) {
+        drawLabelsForAxis(0); // X
+        drawLabelsForAxis(2); // Y
+    } else if (plane == SketchGrid::XZ) {
+        drawLabelsForAxis(0); // X
+        drawLabelsForAxis(1); // Z
+    } else if (plane == SketchGrid::YZ) {
+        drawLabelsForAxis(1); // Y
+        drawLabelsForAxis(2); // Z
+    }
+}

src/SketchGrid.h

@@ -7,6 +7,8 @@
 #include <QOpenGLBuffer>
 
 class QOpenGLShaderProgram;
+class QPainter;
+class ViewportWidget;
 
 class SketchGrid : protected QOpenGLFunctions
 {
@@ -17,11 +19,12 @@ public:
         YZ = 3
     };
 
-    SketchGrid();
+    explicit SketchGrid(ViewportWidget* viewport);
     ~SketchGrid();
 
     void initializeGL();
     void paintGL(SketchPlane plane, QOpenGLShaderProgram* shaderProgram, int colorLoc);
+    void paintAxisLabels(QPainter& painter, SketchPlane plane, const QMatrix4x4& modelView, const QMatrix4x4& projection);
 
 private:
     void drawGridLines(SketchPlane plane, QOpenGLShaderProgram* shaderProgram, int colorLoc);
@@ -29,6 +32,7 @@ private:
 
     QOpenGLVertexArrayObject m_vao;
     QOpenGLBuffer m_vbo;
+    ViewportWidget* m_viewport = nullptr;
 };
 
 #endif // SKETCHGRID_H

src/SketchObject.h

@@ -7,7 +7,9 @@ class SketchObject
 {
 public:
     enum class ObjectType {
-        Line
+        Line,
+        Rectangle,
+        Circle
     };
 
     SketchObject() = default;

src/SketchRectangle.cpp

@@ -0,0 +1,61 @@
+#include "SketchRectangle.h"
+#include <QJsonArray>
+
+namespace
+{
+    void pointToJson(const gp_Pnt& p, QJsonArray& arr)
+    {
+        arr.append(p.X());
+        arr.append(p.Y());
+        arr.append(p.Z());
+    }
+
+    gp_Pnt jsonToPoint(const QJsonArray& arr)
+    {
+        return gp_Pnt(arr[0].toDouble(), arr[1].toDouble(), arr[2].toDouble());
+    }
+}
+
+SketchRectangle::SketchRectangle()
+{
+}
+
+SketchRectangle::SketchRectangle(const gp_Pnt& corner1, const gp_Pnt& corner2)
+    : m_corner1(corner1), m_corner2(corner2)
+{
+}
+
+SketchObject::ObjectType SketchRectangle::type() const
+{
+    return ObjectType::Rectangle;
+}
+
+void SketchRectangle::read(const QJsonObject& json)
+{
+    if (json.contains("corner1") && json["corner1"].isArray()) {
+        m_corner1 = jsonToPoint(json["corner1"].toArray());
+    }
+    if (json.contains("corner2") && json["corner2"].isArray()) {
+        m_corner2 = jsonToPoint(json["corner2"].toArray());
+    }
+}
+
+void SketchRectangle::write(QJsonObject& json) const
+{
+    json["type"] = "Rectangle";
+    QJsonArray c1, c2;
+    pointToJson(m_corner1, c1);
+    pointToJson(m_corner2, c2);
+    json["corner1"] = c1;
+    json["corner2"] = c2;
+}
+
+const gp_Pnt& SketchRectangle::corner1() const
+{
+    return m_corner1;
+}
+
+const gp_Pnt& SketchRectangle::corner2() const
+{
+    return m_corner2;
+}

src/SketchRectangle.h

@@ -0,0 +1,26 @@
+#ifndef SKETCHRECTANGLE_H
+#define SKETCHRECTANGLE_H
+
+#include "SketchObject.h"
+#include <gp_Pnt.hxx>
+
+class SketchRectangle : public SketchObject
+{
+public:
+    SketchRectangle();
+    SketchRectangle(const gp_Pnt& corner1, const gp_Pnt& corner2);
+
+    ObjectType type() const override;
+
+    void read(const QJsonObject& json) override;
+    void write(QJsonObject& json) const override;
+
+    const gp_Pnt& corner1() const;
+    const gp_Pnt& corner2() const;
+
+private:
+    gp_Pnt m_corner1;
+    gp_Pnt m_corner2;
+};
+
+#endif // SKETCHRECTANGLE_H

src/SketchTool.cpp

@@ -0,0 +1,79 @@
+#include "SketchTool.h"
+#include "ViewportWidget.h"
+#include <QKeyEvent>
+
+SketchTool::SketchTool(ViewportWidget* viewport)
+    : QObject(viewport), m_viewport(viewport)
+{
+}
+
+void SketchTool::activate()
+{
+    m_isDefining = false;
+}
+
+void SketchTool::deactivate()
+{
+    m_isDefining = false;
+    for (const QString& propName : m_dimensionPropertyNames.values()) {
+        m_viewport->setProperty(propName.toUtf8().constData(), "");
+    }
+    m_dimensionModes.clear();
+    m_dimensionPropertyNames.clear();
+}
+
+void SketchTool::keyPressEvent(QKeyEvent *event)
+{
+    if (m_isDefining) {
+        if (event->key() == Qt::Key_Tab) {
+            if (m_dimensionModes.size() > 1) {
+                QString currentMode = m_viewport->property("dimensionEditMode").toString();
+                int currentIndex = m_dimensionModes.indexOf(currentMode);
+                if (currentIndex != -1) {
+                    int nextIndex = (currentIndex + 1) % m_dimensionModes.size();
+                    m_viewport->setProperty("dimensionEditMode", m_dimensionModes[nextIndex]);
+                    m_viewport->update();
+                }
+            }
+            return;
+        }
+
+        QString editMode = m_viewport->property("dimensionEditMode").toString();
+        if (m_dimensionPropertyNames.contains(editMode)) {
+            QString propertyName = m_dimensionPropertyNames[editMode];
+            QString currentInput = m_viewport->property(propertyName.toUtf8().constData()).toString();
+
+            if (event->key() >= Qt::Key_0 && event->key() <= Qt::Key_9) {
+                currentInput += event->text();
+                m_viewport->setProperty(propertyName.toUtf8().constData(), currentInput);
+                m_viewport->update();
+                return;
+            } else if (event->key() == Qt::Key_Period) {
+                if (!currentInput.contains('.')) {
+                    currentInput += '.';
+                    m_viewport->setProperty(propertyName.toUtf8().constData(), currentInput);
+                    m_viewport->update();
+                }
+                return;
+            } else if (event->key() == Qt::Key_Backspace) {
+                if (!currentInput.isEmpty()) {
+                    currentInput.chop(1);
+                    m_viewport->setProperty(propertyName.toUtf8().constData(), currentInput);
+                    m_viewport->update();
+                }
+                return;
+            }
+        }
+
+        if (event->key() == Qt::Key_Return || event->key() == Qt::Key_Enter) {
+            finalizeCreation();
+            m_viewport->update();
+            return;
+        } else if (event->key() == Qt::Key_Escape) {
+            deactivate();
+            m_viewport->deactivateActiveTool();
+            m_viewport->update();
+            return;
+        }
+    }
+}

src/SketchTool.h

@@ -0,0 +1,40 @@
+#ifndef SKETCHTOOL_H
+#define SKETCHTOOL_H
+
+#include <QObject>
+#include <QStringList>
+#include <QMap>
+
+class QMouseEvent;
+class QKeyEvent;
+class ViewportWidget;
+class QOpenGLShaderProgram;
+class QPainter;
+class QMatrix4x4;
+
+class SketchTool : public QObject
+{
+    Q_OBJECT
+public:
+    explicit SketchTool(ViewportWidget* viewport);
+    virtual ~SketchTool() = default;
+
+    virtual void mousePressEvent(QMouseEvent *event) = 0;
+    virtual void mouseMoveEvent(QMouseEvent *event) = 0;
+    virtual void keyPressEvent(QKeyEvent *event);
+
+    virtual void paintGL() = 0;
+    virtual void paint2D(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection) = 0;
+
+    virtual void activate();
+    virtual void deactivate();
+
+protected:
+    virtual void finalizeCreation() = 0;
+    ViewportWidget* m_viewport;
+    bool m_isDefining = false;
+    QStringList m_dimensionModes;
+    QMap<QString, QString> m_dimensionPropertyNames;
+};
+
+#endif // SKETCHTOOL_H

src/Snapping.cpp

@@ -0,0 +1,185 @@
+#include "Snapping.h"
+
+#include "ViewportWidget.h"
+#include "Camera.h"
+#include "Document.h"
+#include "SketchFeature.h"
+#include "SketchLine.h"
+#include "SketchRectangle.h"
+#include "SketchObject.h"
+#include "ApplicationController.h"
+
+#include <QOpenGLShaderProgram>
+#include <QVector>
+#include <QtMath>
+
+Snapping::Snapping(ViewportWidget* viewport) : m_viewport(viewport)
+{
+}
+
+bool Snapping::update(const QPoint& mousePos)
+{
+    bool oldIsSnappingOrigin = m_isSnappingOrigin;
+    bool oldIsSnappingVertex = m_isSnappingVertex;
+
+    bool shouldSnap = false;
+    if (m_viewport->currentPlane() != ViewportWidget::SketchPlane::NONE && m_viewport->activeTool() != static_cast<int>(ApplicationController::ToolType::None)) {
+        QVector3D worldPos = m_viewport->unproject(mousePos, m_viewport->currentPlane());
+        const float snapRectHalfSize = 0.0075f * -m_viewport->camera()->zoom();
+
+        switch (m_viewport->currentPlane()) {
+            case ViewportWidget::SketchPlane::XY:
+                shouldSnap = qAbs(worldPos.x()) < snapRectHalfSize && qAbs(worldPos.z()) < snapRectHalfSize;
+                break;
+            case ViewportWidget::SketchPlane::XZ:
+                shouldSnap = qAbs(worldPos.x()) < snapRectHalfSize && qAbs(worldPos.y()) < snapRectHalfSize;
+                break;
+            case ViewportWidget::SketchPlane::YZ:
+                shouldSnap = qAbs(worldPos.y()) < snapRectHalfSize && qAbs(worldPos.z()) < snapRectHalfSize;
+                break;
+            case ViewportWidget::SketchPlane::NONE:
+                break;
+        }
+    }
+
+    m_isSnappingOrigin = shouldSnap;
+    if (m_isSnappingOrigin) {
+        m_isSnappingVertex = false;
+    }
+
+    m_isSnappingVertex = false;
+    if (!m_isSnappingOrigin && m_viewport->document() && m_viewport->currentPlane() != ViewportWidget::SketchPlane::NONE && m_viewport->activeTool() != static_cast<int>(ApplicationController::ToolType::None)) {
+        QVector3D worldPos = m_viewport->unproject(mousePos, m_viewport->currentPlane());
+        const float snapRectHalfSize = 0.0075f * -m_viewport->camera()->zoom();
+
+        for (Feature* feature : m_viewport->document()->features()) {
+            if (auto sketch = dynamic_cast<SketchFeature*>(feature)) {
+                for (const auto& obj : sketch->objects()) {
+                    if (obj->type() == SketchObject::ObjectType::Line) {
+                        auto line = static_cast<const SketchLine*>(obj);
+                        const gp_Pnt vertices[] = {line->startPoint(), line->endPoint()};
+                        for (const auto& vertex : vertices) {
+                            bool isClose = false;
+                            switch (m_viewport->currentPlane()) {
+                            case ViewportWidget::SketchPlane::XY:
+                                isClose = qAbs(worldPos.x() - vertex.X()) < snapRectHalfSize && qAbs(worldPos.z() - vertex.Z()) < snapRectHalfSize;
+                                break;
+                            case ViewportWidget::SketchPlane::XZ:
+                                isClose = qAbs(worldPos.x() - vertex.X()) < snapRectHalfSize && qAbs(worldPos.y() - vertex.Y()) < snapRectHalfSize;
+                                break;
+                            case ViewportWidget::SketchPlane::YZ:
+                                isClose = qAbs(worldPos.y() - vertex.Y()) < snapRectHalfSize && qAbs(worldPos.z() - vertex.Z()) < snapRectHalfSize;
+                                break;
+                            case ViewportWidget::SketchPlane::NONE:
+                                break;
+                            }
+
+                            if (isClose) {
+                                m_isSnappingVertex = true;
+                                m_snapVertex = vertex;
+                                goto end_snap_check;
+                            }
+                        }
+                    } else if (obj->type() == SketchObject::ObjectType::Rectangle) {
+                        auto rect = static_cast<const SketchRectangle*>(obj);
+                        const auto& p1 = rect->corner1();
+                        const auto& p3 = rect->corner2();
+                        gp_Pnt p2, p4;
+
+                        if (sketch->plane() == SketchFeature::SketchPlane::XY) {
+                            p2.SetCoord(p3.X(), p1.Y(), p1.Z());
+                            p4.SetCoord(p1.X(), p1.Y(), p3.Z());
+                        } else if (sketch->plane() == SketchFeature::SketchPlane::XZ) {
+                            p2.SetCoord(p3.X(), p1.Y(), p1.Z());
+                            p4.SetCoord(p1.X(), p3.Y(), p1.Z());
+                        } else if (sketch->plane() == SketchFeature::SketchPlane::YZ) {
+                            p2.SetCoord(p1.X(), p3.Y(), p1.Z());
+                            p4.SetCoord(p1.X(), p1.Y(), p3.Z());
+                        }
+
+                        const gp_Pnt vertices[] = {p1, p2, p3, p4};
+                        for (const auto& vertex : vertices) {
+                            bool isClose = false;
+                            switch (m_viewport->currentPlane()) {
+                            case ViewportWidget::SketchPlane::XY:
+                                isClose = qAbs(worldPos.x() - vertex.X()) < snapRectHalfSize && qAbs(worldPos.z() - vertex.Z()) < snapRectHalfSize;
+                                break;
+                            case ViewportWidget::SketchPlane::XZ:
+                                isClose = qAbs(worldPos.x() - vertex.X()) < snapRectHalfSize && qAbs(worldPos.y() - vertex.Y()) < snapRectHalfSize;
+                                break;
+                            case ViewportWidget::SketchPlane::YZ:
+                                isClose = qAbs(worldPos.y() - vertex.Y()) < snapRectHalfSize && qAbs(worldPos.z() - vertex.Z()) < snapRectHalfSize;
+                                break;
+                            case ViewportWidget::SketchPlane::NONE:
+                                break;
+                            }
+
+                            if (isClose) {
+                                m_isSnappingVertex = true;
+                                m_snapVertex = vertex;
+                                goto end_snap_check;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    end_snap_check:;
+    }
+
+    return (oldIsSnappingOrigin != m_isSnappingOrigin) || (oldIsSnappingVertex != m_isSnappingVertex);
+}
+
+void Snapping::paintGL() const
+{
+    if (!m_isSnappingOrigin && !m_isSnappingVertex) {
+        return;
+    }
+
+    QVector<GLfloat> vertices;
+    if (m_isSnappingOrigin) {
+        const float rectSize = 0.0075f * -m_viewport->camera()->zoom();
+        if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+            vertices << -rectSize << 0 << -rectSize << rectSize << 0 << -rectSize;
+            vertices << rectSize << 0 << -rectSize << rectSize << 0 << rectSize;
+            vertices << rectSize << 0 << rectSize << -rectSize << 0 << rectSize;
+            vertices << -rectSize << 0 << rectSize << -rectSize << 0 << -rectSize;
+        } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+            vertices << -rectSize << -rectSize << 0 << rectSize << -rectSize << 0;
+            vertices << rectSize << -rectSize << 0 << rectSize << rectSize << 0;
+            vertices << rectSize << rectSize << 0 << -rectSize << rectSize << 0;
+            vertices << -rectSize << rectSize << 0 << -rectSize << -rectSize << 0;
+        } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::YZ) {
+            vertices << 0 << -rectSize << -rectSize << 0 << rectSize << -rectSize;
+            vertices << 0 << rectSize << -rectSize << 0 << rectSize << rectSize;
+            vertices << 0 << rectSize << rectSize << 0 << -rectSize << rectSize;
+            vertices << 0 << -rectSize << rectSize << 0 << -rectSize << -rectSize;
+        }
+    } else if (m_isSnappingVertex) {
+        const float rectSize = 0.0075f * -m_viewport->camera()->zoom();
+        const auto& v = m_snapVertex;
+        if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XY) {
+            vertices << v.X() - rectSize << v.Y() << v.Z() - rectSize << v.X() + rectSize << v.Y() << v.Z() - rectSize;
+            vertices << v.X() + rectSize << v.Y() << v.Z() - rectSize << v.X() + rectSize << v.Y() << v.Z() + rectSize;
+            vertices << v.X() + rectSize << v.Y() << v.Z() + rectSize << v.X() - rectSize << v.Y() << v.Z() + rectSize;
+            vertices << v.X() - rectSize << v.Y() << v.Z() + rectSize << v.X() - rectSize << v.Y() << v.Z() - rectSize;
+        } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::XZ) {
+            vertices << v.X() - rectSize << v.Y() - rectSize << v.Z() << v.X() + rectSize << v.Y() - rectSize << v.Z();
+            vertices << v.X() + rectSize << v.Y() - rectSize << v.Z() << v.X() + rectSize << v.Y() + rectSize << v.Z();
+            vertices << v.X() + rectSize << v.Y() + rectSize << v.Z() << v.X() - rectSize << v.Y() + rectSize << v.Z();
+            vertices << v.X() - rectSize << v.Y() + rectSize << v.Z() << v.X() - rectSize << v.Y() - rectSize << v.Z();
+        } else if (m_viewport->currentPlane() == ViewportWidget::SketchPlane::YZ) {
+            vertices << v.X() << v.Y() - rectSize << v.Z() - rectSize << v.X() << v.Y() + rectSize << v.Z() - rectSize;
+            vertices << v.X() << v.Y() + rectSize << v.Z() - rectSize << v.X() << v.Y() + rectSize << v.Z() + rectSize;
+            vertices << v.X() << v.Y() + rectSize << v.Z() + rectSize << v.X() << v.Y() - rectSize << v.Z() + rectSize;
+            vertices << v.X() << v.Y() - rectSize << v.Z() + rectSize << v.X() << v.Y() - rectSize << v.Z() - rectSize;
+        }
+    }
+    m_viewport->shaderProgram()->setUniformValue(m_viewport->colorLoc(), QVector4D(1.0f, 1.0f, 0.0f, 0.5f));
+    m_viewport->vbo().bind();
+    m_viewport->vbo().allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+    glDrawArrays(GL_LINES, 0, vertices.size() / 3);
+    glDisable(GL_BLEND);
+}

src/Snapping.h

@@ -0,0 +1,28 @@
+#ifndef SNAPPING_H
+#define SNAPPING_H
+
+#include <gp_Pnt.hxx>
+#include <QPoint>
+
+class ViewportWidget;
+
+class Snapping
+{
+public:
+    explicit Snapping(ViewportWidget* viewport);
+
+    bool update(const QPoint& mousePos);
+    void paintGL() const;
+
+    bool isSnappingOrigin() const { return m_isSnappingOrigin; }
+    bool isSnappingVertex() const { return m_isSnappingVertex; }
+    const gp_Pnt& snapVertex() const { return m_snapVertex; }
+
+private:
+    ViewportWidget* m_viewport = nullptr;
+    bool m_isSnappingOrigin = false;
+    bool m_isSnappingVertex = false;
+    gp_Pnt m_snapVertex;
+};
+
+#endif // SNAPPING_H

src/ViewCube.cpp

@@ -1,12 +1,30 @@
 #include "ViewCube.h"
+#include <QGuiApplication>
 #include <QPainter>
 #include <QFont>
 #include <QOpenGLShaderProgram>
 #include <QOpenGLTexture>
+#include <QScreen>
+#include <QSvgRenderer>
 #include <QVector>
 
+namespace
+{
+QRect getHomeButtonRect(int widgetWidth) {
+    const int viewCubeSize = 150; // logical pixels
+    const int buttonSize = 24;
+    const int buttonOffsetX = 16;
+    const int buttonOffsetY = 16;
+
+    const int viewCubeX = widgetWidth - viewCubeSize;
+
+    return QRect(viewCubeX + buttonOffsetX, buttonOffsetY, buttonSize, buttonSize);
+}
+}
+
 ViewCube::ViewCube()
 {
+    m_homeButtonRenderer = new QSvgRenderer(QString(":/icons/home.svg"));
     for (int i = 0; i < 6; ++i) {
         m_faceTextures[i] = nullptr;
     }
@@ -18,6 +36,7 @@ ViewCube::~ViewCube()
         delete m_faceTextures[i];
     }
     delete m_textureShaderProgram;
+    delete m_homeButtonRenderer;
     m_cubeVbo.destroy();
     m_cubeVao.destroy();
     m_axesVbo.destroy();
@@ -32,17 +51,30 @@ void ViewCube::initializeGL()
     setupBuffers();
 }
 
-void ViewCube::paintGL(QOpenGLShaderProgram* simpleShader, int simpleShaderColorLoc, const QMatrix4x4& viewMatrix, int width, int height)
+void ViewCube::paintGL(QOpenGLShaderProgram* simpleShader, int simpleShaderColorLoc, const QMatrix4x4& viewMatrix, int width, int height, const QPoint& mousePos)
 {
-    int viewCubeSize = 150;
+    int viewCubeSize = 150 * QGuiApplication::primaryScreen()->devicePixelRatio();
     glViewport(width - viewCubeSize, height - viewCubeSize, viewCubeSize, viewCubeSize);
+
+    QRect viewCubeRect(width - viewCubeSize, 0, viewCubeSize, viewCubeSize);
+    QPoint physicalMousePos = mousePos * QGuiApplication::primaryScreen()->devicePixelRatio();
+
+    m_isHovered = viewCubeRect.contains(physicalMousePos);
+
+    float opacity = m_isHovered ? 1.0f : 0.5f;
+
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
     glClear(GL_DEPTH_BUFFER_BIT);
 
     QMatrix4x4 viewCubeProjection;
     viewCubeProjection.ortho(-2, 2, -2, 2, -10, 10);
 
-    drawViewCube(viewCubeProjection, viewMatrix);
+    drawViewCube(viewCubeProjection, viewMatrix, opacity);
     drawAxes(simpleShader, simpleShaderColorLoc, viewCubeProjection, viewMatrix);
+
+    glDisable(GL_BLEND);
 }
 
 void ViewCube::createFaceTextures()
@@ -144,7 +176,7 @@ void ViewCube::setupBuffers()
     m_axesVbo.release();
 }
 
-void ViewCube::drawViewCube(const QMatrix4x4& projection, const QMatrix4x4& view)
+void ViewCube::drawViewCube(const QMatrix4x4& projection, const QMatrix4x4& view, float opacity)
 {
     if (!m_textureShaderProgram || !m_textureShaderProgram->isLinked()) return;
 
@@ -153,6 +185,7 @@ void ViewCube::drawViewCube(const QMatrix4x4& projection, const QMatrix4x4& view
     m_textureShaderProgram->setUniformValue("projectionMatrix", projection);
     m_textureShaderProgram->setUniformValue("modelViewMatrix", view);
     m_textureShaderProgram->setUniformValue("texture_diffuse1", 0);
+    m_textureShaderProgram->setUniformValue("opacity", opacity);
 
     QOpenGLVertexArrayObject::Binder vaoBinder(&m_cubeVao);
     for (int i = 0; i < 6; ++i) {
@@ -193,3 +226,27 @@ void ViewCube::drawAxes(QOpenGLShaderProgram* simpleShader, int colorLoc, const
 
     glLineWidth(1.0f);
 }
+
+void ViewCube::paint2D(QPainter& painter, int widgetWidth, int widgetHeight)
+{
+    if (!m_isHovered) {
+        return;
+    }
+
+    m_homeButtonRect = getHomeButtonRect(widgetWidth);
+
+    if (m_homeButtonRenderer && m_homeButtonRenderer->isValid()) {
+        m_homeButtonRenderer->render(&painter, m_homeButtonRect);
+    }
+}
+
+bool ViewCube::handleMousePress(const QPoint& pos, int widgetWidth, int widgetHeight)
+{
+    if (!m_isHovered) {
+        return false;
+    }
+
+    QRect homeButtonRect = getHomeButtonRect(widgetWidth);
+
+    return homeButtonRect.contains(pos);
+}

src/ViewCube.h

@@ -5,9 +5,12 @@
 #include <QMatrix4x4>
 #include <QOpenGLVertexArrayObject>
 #include <QOpenGLBuffer>
+#include <QPoint>
 
 class QOpenGLShaderProgram;
 class QOpenGLTexture;
+class QPainter;
+class QSvgRenderer;
 
 class ViewCube : protected QOpenGLFunctions
 {
@@ -16,15 +19,21 @@ public:
     ~ViewCube();
 
     void initializeGL();
-    void paintGL(QOpenGLShaderProgram* simpleShader, int simpleShaderColorLoc, const QMatrix4x4& viewMatrix, int width, int height);
+    void paintGL(QOpenGLShaderProgram* simpleShader, int simpleShaderColorLoc, const QMatrix4x4& viewMatrix, int width, int height, const QPoint& mousePos);
+    void paint2D(QPainter& painter, int widgetWidth, int widgetHeight);
+    bool handleMousePress(const QPoint& pos, int widgetWidth, int widgetHeight);
 
 private:
     void createFaceTextures();
     void initShaders();
     void setupBuffers();
-    void drawViewCube(const QMatrix4x4& projection, const QMatrix4x4& view);
+    void drawViewCube(const QMatrix4x4& projection, const QMatrix4x4& view, float opacity);
     void drawAxes(QOpenGLShaderProgram* simpleShader, int colorLoc, const QMatrix4x4& projection, const QMatrix4x4& view);
 
+    bool m_isHovered = false;
+    QRect m_homeButtonRect;
+    QSvgRenderer* m_homeButtonRenderer = nullptr;
+
     QOpenGLTexture* m_faceTextures[6];
 
     QOpenGLShaderProgram* m_textureShaderProgram = nullptr;

src/ViewportWidget.cpp

@@ -1,4 +1,5 @@
 #include "ViewportWidget.h"
+#include "Snapping.h"
 #include "Camera.h"
 #include "ViewCube.h"
 #include "SketchGrid.h"
@@ -6,8 +7,13 @@
 #include "FeatureBrowser.h"
 #include "SketchFeature.h"
 #include "SketchLine.h"
+#include "SketchRectangle.h"
+#include "SketchCircle.h"
 #include "SketchObject.h"
 #include "ApplicationController.h"
+#include "RectangleTool.h"
+#include "LineTool.h"
+#include "CircleTool.h"
 #include <QMouseEvent>
 #include <QKeyEvent>
 #include <QWheelEvent>
@@ -18,13 +24,20 @@
 #include <QSvgRenderer>
 #include <QWheelEvent>
 #include <QApplication>
-#include <QPropertyAnimation>
-#include <QParallelAnimationGroup>
 #include <cmath>
 #include <QtMath>
 #include <QOpenGLShaderProgram>
 #include <QVector>
-#include <QMap>
+#include <map>
+
+#include <BRepMesh_IncrementalMesh.hxx>
+#include <TopExp_Explorer.hxx>
+#include <TopoDS.hxx>
+#include <TopoDS_Face.hxx>
+#include <Poly_Triangulation.hxx>
+#include <BRep_Tool.hxx>
+#include <gp_Dir.hxx>
+#include <gp_Trsf.hxx>
 
 struct PntComparator {
     bool operator()(const gp_Pnt& a, const gp_Pnt& b) const {
@@ -42,8 +55,9 @@ ViewportWidget::ViewportWidget(QWidget *parent)
 {
     m_camera = new Camera(this);
     connect(m_camera, &Camera::cameraChanged, this, QOverload<>::of(&QWidget::update));
+    connect(m_camera, &Camera::restoreStateAnimationFinished, this, &ViewportWidget::onRestoreStateAnimationFinished);
     m_viewCube = new ViewCube();
-    m_sketchGrid = new SketchGrid();
+    m_sketchGrid = new SketchGrid(this);
     m_featureBrowser = new FeatureBrowser();
     setMouseTracking(true);
     setFocusPolicy(Qt::StrongFocus);
@@ -55,12 +69,19 @@ ViewportWidget::ViewportWidget(QWidget *parent)
     m_toolIcons.insert(static_cast<int>(ApplicationController::ToolType::Circle), new QSvgRenderer(QString(":/icons/circle.svg"), this));
 
     m_cursorRenderer = new QSvgRenderer(QString(":/icons/cursor.svg"), this);
+
+    m_sketchTools.insert(static_cast<int>(ApplicationController::ToolType::Line), new LineTool(this));
+    m_sketchTools.insert(static_cast<int>(ApplicationController::ToolType::Rectangle), new RectangleTool(this));
+    m_sketchTools.insert(static_cast<int>(ApplicationController::ToolType::Circle), new CircleTool(this));
+
+    m_snapping = new Snapping(this);
 }
 
 ViewportWidget::~ViewportWidget()
 {
     makeCurrent();
     delete m_shaderProgram;
+    delete m_litShaderProgram;
     delete m_viewCube;
     delete m_sketchGrid;
     m_vbo.destroy();
@@ -68,6 +89,7 @@ ViewportWidget::~ViewportWidget()
     doneCurrent();
 
     delete m_featureBrowser;
+    delete m_snapping;
 }
 
 void ViewportWidget::setDocument(Document* document)
@@ -102,8 +124,10 @@ void ViewportWidget::initializeGL()
 
 void ViewportWidget::paintGL()
 {
+    const qreal retinaScale = devicePixelRatio();
+
     // Main scene rendering
-    glViewport(0, 0, width(), height());
+    glViewport(0, 0, width() * retinaScale, height() * retinaScale);
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
     if (!m_shaderProgram || !m_shaderProgram->isLinked()) {
@@ -142,117 +166,33 @@ void ViewportWidget::paintGL()
         }
     }
 
-    QVector<GLfloat> vertices;
-    if (m_isSnappingOrigin) {
-        const float rectSize = 0.0075f * -m_camera->zoom();
-        if (m_currentPlane == SketchPlane::XY) {
-            vertices << -rectSize << 0 << -rectSize << rectSize << 0 << -rectSize;
-            vertices << rectSize << 0 << -rectSize << rectSize << 0 << rectSize;
-            vertices << rectSize << 0 << rectSize << -rectSize << 0 << rectSize;
-            vertices << -rectSize << 0 << rectSize << -rectSize << 0 << -rectSize;
-        } else if (m_currentPlane == SketchPlane::XZ) {
-            vertices << -rectSize << -rectSize << 0 << rectSize << -rectSize << 0;
-            vertices << rectSize << -rectSize << 0 << rectSize << rectSize << 0;
-            vertices << rectSize << rectSize << 0 << -rectSize << rectSize << 0;
-            vertices << -rectSize << rectSize << 0 << -rectSize << -rectSize << 0;
-        } else if (m_currentPlane == SketchPlane::YZ) {
-            vertices << 0 << -rectSize << -rectSize << 0 << rectSize << -rectSize;
-            vertices << 0 << rectSize << -rectSize << 0 << rectSize << rectSize;
-            vertices << 0 << rectSize << rectSize << 0 << -rectSize << rectSize;
-            vertices << 0 << -rectSize << rectSize << 0 << -rectSize << -rectSize;
-        }
-        m_shaderProgram->setUniformValue(m_colorLoc, QVector4D(1.0f, 1.0f, 0.0f, 0.5f));
-        m_vbo.bind();
-        m_vbo.allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
-        glEnable(GL_BLEND);
-        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-        glDrawArrays(GL_LINES, 0, vertices.size() / 3);
-        glDisable(GL_BLEND);
-    } else if (m_isSnappingVertex) {
-        const float rectSize = 0.0075f * -m_camera->zoom();
-        const auto& v = m_snapVertex;
-        if (m_currentPlane == SketchPlane::XY) {
-            vertices << v.X() - rectSize << v.Y() << v.Z() - rectSize << v.X() + rectSize << v.Y() << v.Z() - rectSize;
-            vertices << v.X() + rectSize << v.Y() << v.Z() - rectSize << v.X() + rectSize << v.Y() << v.Z() + rectSize;
-            vertices << v.X() + rectSize << v.Y() << v.Z() + rectSize << v.X() - rectSize << v.Y() << v.Z() + rectSize;
-            vertices << v.X() - rectSize << v.Y() << v.Z() + rectSize << v.X() - rectSize << v.Y() << v.Z() - rectSize;
-        } else if (m_currentPlane == SketchPlane::XZ) {
-            vertices << v.X() - rectSize << v.Y() - rectSize << v.Z() << v.X() + rectSize << v.Y() - rectSize << v.Z();
-            vertices << v.X() + rectSize << v.Y() - rectSize << v.Z() << v.X() + rectSize << v.Y() + rectSize << v.Z();
-            vertices << v.X() + rectSize << v.Y() + rectSize << v.Z() << v.X() - rectSize << v.Y() + rectSize << v.Z();
-            vertices << v.X() - rectSize << v.Y() + rectSize << v.Z() << v.X() - rectSize << v.Y() - rectSize << v.Z();
-        } else if (m_currentPlane == SketchPlane::YZ) {
-            vertices << v.X() << v.Y() - rectSize << v.Z() - rectSize << v.X() << v.Y() + rectSize << v.Z() - rectSize;
-            vertices << v.X() << v.Y() + rectSize << v.Z() - rectSize << v.X() << v.Y() + rectSize << v.Z() + rectSize;
-            vertices << v.X() << v.Y() + rectSize << v.Z() + rectSize << v.X() << v.Y() - rectSize << v.Z() + rectSize;
-            vertices << v.X() << v.Y() - rectSize << v.Z() + rectSize << v.X() << v.Y() - rectSize << v.Z() - rectSize;
-        }
-        m_shaderProgram->setUniformValue(m_colorLoc, QVector4D(1.0f, 1.0f, 0.0f, 0.5f));
-        m_vbo.bind();
-        m_vbo.allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
-        glEnable(GL_BLEND);
-        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-        glDrawArrays(GL_LINES, 0, vertices.size() / 3);
-        glDisable(GL_BLEND);
+    m_snapping->paintGL();
+
+    if (m_camera->isRotating()) {
+        const float radius = 0.004f * -m_camera->uiCameraDistance();
+        const int numSegments = 16;
+        QMatrix4x4 invModelView = m_camera->modelViewMatrix().inverted();
+        QVector3D rightVec = invModelView.column(0).toVector3D();
+        QVector3D upVec = invModelView.column(1).toVector3D();
+
+        QVector<GLfloat> circleFillVertices;
+        QVector3D center = m_camera->rotationPivot();
+
+        circleFillVertices << center.x() << center.y() << center.z(); // Center vertex for fan
+        for (int i = 0; i <= numSegments; ++i) { // <= to close the circle
+            float angle = (2.0f * M_PI * float(i)) / float(numSegments);
+            QVector3D p = center + radius * (cos(angle) * rightVec + sin(angle) * upVec);
+            circleFillVertices << p.x() << p.y() << p.z();
         }
 
-    if (m_isDefiningLine && m_activeTool == static_cast<int>(ApplicationController::ToolType::Line)) {
-        vertices.clear();
-        QVector3D worldPos = unproject(m_currentMousePos, m_currentPlane);
-        if (m_isSnappingOrigin) {
-            worldPos.setX(0); worldPos.setY(0); worldPos.setZ(0);
-        } else if (m_isSnappingVertex) {
-            worldPos.setX(m_snapVertex.X()); worldPos.setY(m_snapVertex.Y()); worldPos.setZ(m_snapVertex.Z());
-        } else if (m_isSnappingHorizontal) {
-            if (m_currentPlane == SketchPlane::XY) worldPos.setZ(m_firstLinePoint.Z());
-            else if (m_currentPlane == SketchPlane::XZ) worldPos.setY(m_firstLinePoint.Y());
-            else if (m_currentPlane == SketchPlane::YZ) worldPos.setZ(m_firstLinePoint.Z());
-        } else if (m_isSnappingVertical) {
-            if (m_currentPlane == SketchPlane::XY) worldPos.setX(m_firstLinePoint.X());
-            else if (m_currentPlane == SketchPlane::XZ) worldPos.setX(m_firstLinePoint.X());
-            else if (m_currentPlane == SketchPlane::YZ) worldPos.setY(m_firstLinePoint.Y());
-        }
-        vertices << m_firstLinePoint.X() << m_firstLinePoint.Y() << m_firstLinePoint.Z();
-        vertices << worldPos.x() << worldPos.y() << worldPos.z();
-
-        m_shaderProgram->setUniformValue(m_colorLoc, QVector4D(1.0f, 1.0f, 0.0f, 1.0f));
+        m_shaderProgram->setUniformValue(m_colorLoc, QVector4D(0.0f, 0.0f, 1.0f, 1.0f)); // Blue
         m_vbo.bind();
-        m_vbo.allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
-        glDrawArrays(GL_LINES, 0, 2);
+        m_vbo.allocate(circleFillVertices.constData(), circleFillVertices.size() * sizeof(GLfloat));
+        glDrawArrays(GL_TRIANGLE_FAN, 0, circleFillVertices.size() / 3);
+    }
 
-        if (m_isSnappingHorizontal || m_isSnappingVertical) {
-            vertices.clear();
-            QVector3D startPos(m_firstLinePoint.X(), m_firstLinePoint.Y(), m_firstLinePoint.Z());
-            QVector3D midPoint = (startPos + worldPos) / 2.0;
-            const float indicatorSize = 0.02f * -m_camera->zoom();
-            const float indicatorOffset = 0.02f * -m_camera->zoom();
-            if (m_isSnappingHorizontal) {
-                if (m_currentPlane == SketchPlane::XY) {
-                    vertices << midPoint.x() - indicatorSize << midPoint.y() << midPoint.z() + indicatorOffset;
-                    vertices << midPoint.x() + indicatorSize << midPoint.y() << midPoint.z() + indicatorOffset;
-                } else if (m_currentPlane == SketchPlane::XZ) {
-                    vertices << midPoint.x() - indicatorSize << midPoint.y() + indicatorOffset << midPoint.z();
-                    vertices << midPoint.x() + indicatorSize << midPoint.y() + indicatorOffset << midPoint.z();
-                } else if (m_currentPlane == SketchPlane::YZ) {
-                    vertices << midPoint.x() << midPoint.y() - indicatorSize << midPoint.z() + indicatorOffset;
-                    vertices << midPoint.x() << midPoint.y() + indicatorSize << midPoint.z() + indicatorOffset;
-                }
-            } else { // m_isSnappingVertical
-                if (m_currentPlane == SketchPlane::XY) {
-                    vertices << midPoint.x() + indicatorOffset << midPoint.y() << midPoint.z() - indicatorSize;
-                    vertices << midPoint.x() + indicatorOffset << midPoint.y() << midPoint.z() + indicatorSize;
-                } else if (m_currentPlane == SketchPlane::XZ) {
-                    vertices << midPoint.x() + indicatorOffset << midPoint.y() - indicatorSize << midPoint.z();
-                    vertices << midPoint.x() + indicatorOffset << midPoint.y() + indicatorSize << midPoint.z();
-                } else if (m_currentPlane == SketchPlane::YZ) {
-                    vertices << midPoint.x() << midPoint.y() + indicatorOffset << midPoint.z() - indicatorSize;
-                    vertices << midPoint.x() << midPoint.y() + indicatorOffset << midPoint.z() + indicatorSize;
-                }
-            }
-            m_vbo.bind();
-            m_vbo.allocate(vertices.constData(), vertices.size() * sizeof(GLfloat));
-            glDrawArrays(GL_LINES, 0, 2);
-        }
+    if (m_activeSketchTool) {
+        m_activeSketchTool->paintGL();
     }
 
     m_shaderProgram->release();
@@ -261,17 +201,26 @@ void ViewportWidget::paintGL()
     QMatrix4x4 viewCubeModel;
     viewCubeModel.rotate(m_camera->xRotation() / 16.0f, 1, 0, 0);
     viewCubeModel.rotate(m_camera->yRotation() / 16.0f, 0, 1, 0);
-    m_viewCube->paintGL(m_shaderProgram, m_colorLoc, viewCubeModel, width(), height());
+    m_viewCube->paintGL(m_shaderProgram, m_colorLoc, viewCubeModel, width() * retinaScale, height() * retinaScale, m_currentMousePos);
 
-    glViewport(0, 0, width(), height());
+    glViewport(0, 0, width() * retinaScale, height() * retinaScale);
     glDisable(GL_DEPTH_TEST);
     glDisable(GL_CULL_FACE);
 
     QPainter painter(this);
     if (m_currentPlane != SketchPlane::NONE) {
-        drawAxisLabels(painter, model, projection);
+        m_sketchGrid->paintAxisLabels(painter, static_cast<SketchGrid::SketchPlane>(m_currentPlane), model, projection);
     }
     m_featureBrowser->paint(painter, width(), height());
+    m_viewCube->paint2D(painter, width(), height());
+
+
+    if (m_activeSketchTool) {
+        m_activeSketchTool->paint2D(painter, model, projection);
+    }
+
+    painter.setPen(Qt::white);
+    painter.drawText(width() - 350, height() - 10, QString("Camera Distance: %1").arg(-m_camera->uiCameraDistance()));
 
     painter.end();
 }
@@ -279,12 +228,25 @@ void ViewportWidget::paintGL()
 void ViewportWidget::resizeGL(int w, int h)
 {
     projection.setToIdentity();
-    projection.perspective(45.0f, w / float(h), 0.01f, 100.0f);
+    projection.perspective(45.0f, w / float(h), 0.01f, 10000.0f);
 }
 
 void ViewportWidget::mousePressEvent(QMouseEvent *event)
 {
+    m_camera->mousePressEvent(event);
+
+    if (event->button() == Qt::MiddleButton && !(QApplication::keyboardModifiers() & Qt::ShiftModifier)) {
+        m_camera->startRotation(unproject(event->pos(), m_currentPlane));
+        update();
+    }
+
     if (event->button() == Qt::LeftButton) {
+        if (m_viewCube->handleMousePress(event->pos(), width(), height())) {
+            m_camera->animateToHomeView();
+            update();
+            return;
+        }
+
         if (m_isSelectingPlane) {
             if (m_highlightedPlane != SketchPlane::NONE) {
                 emit planeSelected(m_highlightedPlane);
@@ -295,37 +257,12 @@ void ViewportWidget::mousePressEvent(QMouseEvent *event)
             return;
         }
 
-        if (m_currentPlane != SketchPlane::NONE && m_activeTool == static_cast<int>(ApplicationController::ToolType::Line)) {
-            gp_Pnt p;
-            if (m_isSnappingOrigin) {
-                p.SetCoord(0, 0, 0);
-            } else if (m_isSnappingVertex) {
-                p = m_snapVertex;
-            } else {
-                QVector3D worldPos = unproject(event->pos(), m_currentPlane);
-                if (m_isSnappingHorizontal) {
-                    if (m_currentPlane == SketchPlane::XY) worldPos.setZ(m_firstLinePoint.Z());
-                else if (m_currentPlane == SketchPlane::XZ) worldPos.setY(m_firstLinePoint.Y());
-                else if (m_currentPlane == SketchPlane::YZ) worldPos.setZ(m_firstLinePoint.Z());
-            } else if (m_isSnappingVertical) {
-                if (m_currentPlane == SketchPlane::XY) worldPos.setX(m_firstLinePoint.X());
-                else if (m_currentPlane == SketchPlane::XZ) worldPos.setX(m_firstLinePoint.X());
-                else if (m_currentPlane == SketchPlane::YZ) worldPos.setY(m_firstLinePoint.Y());
-            }
-            p.SetCoord(worldPos.x(), worldPos.y(), worldPos.z());
+        if (m_activeSketchTool) {
+            m_activeSketchTool->mousePressEvent(event);
+            update();
+            return;
         }
 
-        if (!m_isDefiningLine) {
-            m_firstLinePoint = p;
-            m_isDefiningLine = true;
-        } else {
-            emit lineAdded(m_firstLinePoint, p);
-            m_firstLinePoint = p;
-            }
-            update();
-        }
-    } else {
-        lastPos = event->pos();
     }
 }
 
@@ -341,208 +278,106 @@ void ViewportWidget::mouseMoveEvent(QMouseEvent *event)
         }
     }
 
-    bool shouldSnap = false;
-    if (m_currentPlane != SketchPlane::NONE && m_activeTool != static_cast<int>(ApplicationController::ToolType::None)) {
-        QVector3D worldPos = unproject(m_currentMousePos, m_currentPlane);
-        const float snapRectHalfSize = 0.0075f * -m_camera->zoom();
-
-        switch (m_currentPlane) {
-            case SketchPlane::XY:
-                shouldSnap = qAbs(worldPos.x()) < snapRectHalfSize && qAbs(worldPos.z()) < snapRectHalfSize;
-                break;
-            case SketchPlane::XZ:
-                shouldSnap = qAbs(worldPos.x()) < snapRectHalfSize && qAbs(worldPos.y()) < snapRectHalfSize;
-                break;
-            case SketchPlane::YZ:
-                shouldSnap = qAbs(worldPos.y()) < snapRectHalfSize && qAbs(worldPos.z()) < snapRectHalfSize;
-                break;
-            case SketchPlane::NONE:
-                break;
-        }
-    }
-
-    if (shouldSnap != m_isSnappingOrigin) {
-        m_isSnappingOrigin = shouldSnap;
-        if (m_isSnappingOrigin) {
-            m_isSnappingVertex = false;
-        }
+    if (m_snapping->update(m_currentMousePos)) {
         update();
     }
 
-    bool oldIsSnappingVertex = m_isSnappingVertex;
-    m_isSnappingVertex = false;
-    if (!m_isSnappingOrigin && m_document && m_currentPlane != SketchPlane::NONE && m_activeTool != static_cast<int>(ApplicationController::ToolType::None)) {
-        QVector3D worldPos = unproject(m_currentMousePos, m_currentPlane);
-        const float snapRectHalfSize = 0.0075f * -m_camera->zoom();
-
-        for (Feature* feature : m_document->features()) {
-            if (auto sketch = dynamic_cast<SketchFeature*>(feature)) {
-                for (const auto& obj : sketch->objects()) {
-                    if (obj->type() == SketchObject::ObjectType::Line) {
-                        auto line = static_cast<const SketchLine*>(obj);
-                        const gp_Pnt vertices[] = {line->startPoint(), line->endPoint()};
-                        for (const auto& vertex : vertices) {
-                            bool isClose = false;
-                            switch (m_currentPlane) {
-                            case SketchPlane::XY:
-                                isClose = qAbs(worldPos.x() - vertex.X()) < snapRectHalfSize && qAbs(worldPos.z() - vertex.Z()) < snapRectHalfSize;
-                                break;
-                            case SketchPlane::XZ:
-                                isClose = qAbs(worldPos.x() - vertex.X()) < snapRectHalfSize && qAbs(worldPos.y() - vertex.Y()) < snapRectHalfSize;
-                                break;
-                            case SketchPlane::YZ:
-                                isClose = qAbs(worldPos.y() - vertex.Y()) < snapRectHalfSize && qAbs(worldPos.z() - vertex.Z()) < snapRectHalfSize;
-                                break;
-                            case SketchPlane::NONE:
-                                break;
+    if (m_activeSketchTool) {
+        m_activeSketchTool->mouseMoveEvent(event);
     }
 
-                            if (isClose) {
-                                m_isSnappingVertex = true;
-                                m_snapVertex = vertex;
-                                goto end_snap_check;
-                            }
-                        }
-                    }
-                }
-            }
-        }
-    end_snap_check:;
-    }
-
-    if (oldIsSnappingVertex != m_isSnappingVertex) {
-        update();
-    }
-
-    bool oldIsSnappingHorizontal = m_isSnappingHorizontal;
-    bool oldIsSnappingVertical = m_isSnappingVertical;
-    m_isSnappingHorizontal = false;
-    m_isSnappingVertical = false;
-
-    if (m_isDefiningLine && !m_isSnappingOrigin && !m_isSnappingVertex) {
-        QVector3D worldPos = unproject(m_currentMousePos, m_currentPlane);
-        QVector3D startPos(m_firstLinePoint.X(), m_firstLinePoint.Y(), m_firstLinePoint.Z());
-        QVector3D delta = worldPos - startPos;
-
-        if (delta.length() > 1e-6) {
-            const double snapAngleThreshold = qDegreesToRadians(2.0);
-            double angle = 0;
-
-            if (m_currentPlane == SketchPlane::XY) {
-                angle = atan2(delta.z(), delta.x());
-            } else if (m_currentPlane == SketchPlane::XZ) {
-                angle = atan2(delta.y(), delta.x());
-            } else if (m_currentPlane == SketchPlane::YZ) {
-                angle = atan2(delta.z(), delta.y());
-            }
-
-            if (qAbs(sin(angle)) < sin(snapAngleThreshold)) {
-                m_isSnappingHorizontal = true;
-            } else if (qAbs(cos(angle)) < sin(snapAngleThreshold)) {
-                m_isSnappingVertical = true;
-            }
-        }
-    }
-
-    if (oldIsSnappingHorizontal != m_isSnappingHorizontal || oldIsSnappingVertical != m_isSnappingVertical) {
-        update();
-    }
-
-    if (event->buttons() & Qt::MiddleButton) {
-        m_camera->processMouseMovement(event, lastPos);
-    }
-    lastPos = event->pos();
+    m_camera->mouseMoveEvent(event, height());
     update();
 }
 
 void ViewportWidget::wheelEvent(QWheelEvent *event)
 {
-    m_camera->processWheel(event);
+    QVector3D worldPos = unproject(event->position().toPoint(), m_currentPlane);
+    m_camera->wheelEvent(event, worldPos);
 }
 
 void ViewportWidget::keyPressEvent(QKeyEvent *event)
 {
-    if (event->key() == Qt::Key_Escape) {
-        if (m_isDefiningLine) {
-            m_isDefiningLine = false;
-            emit toolDeactivated();
-            update();
+    if (m_activeSketchTool) {
+        m_activeSketchTool->keyPressEvent(event);
         return;
     }
+
+    if (event->key() == Qt::Key_Escape) {
 		if (m_isSelectingPlane) {
             m_isSelectingPlane = false;
             m_highlightedPlane = SketchPlane::NONE;
             m_currentPlane = SketchPlane::XY;
             update();
             return;
+        }
+		else if (m_activeTool) {
+            emit toolDeactivated();
+            update();
+            return;
         }
     }
     QOpenGLWidget::keyPressEvent(event);
 }
 
+void ViewportWidget::mouseReleaseEvent(QMouseEvent *event)
+{
+    if (event->button() == Qt::MiddleButton) {
+        m_camera->stopRotation();
+        update();
+    }
+    QOpenGLWidget::mouseReleaseEvent(event);
+}
+
+void ViewportWidget::addLine(const gp_Pnt& start, const gp_Pnt& end)
+{
+    emit lineAdded(start, end);
+}
+
+void ViewportWidget::deactivateActiveTool()
+{
+    emit toolDeactivated();
+}
+
+bool ViewportWidget::isSnappingOrigin() const
+{
+    return m_snapping->isSnappingOrigin();
+}
+
+bool ViewportWidget::isSnappingVertex() const
+{
+    return m_snapping->isSnappingVertex();
+}
+
+const gp_Pnt& ViewportWidget::snapVertex() const
+{
+    return m_snapping->snapVertex();
+}
+
+void ViewportWidget::setSnappingHorizontal(bool snapping)
+{
+    m_isSnappingHorizontal = snapping;
+}
+
+void ViewportWidget::setSnappingVertical(bool snapping)
+{
+    m_isSnappingVertical = snapping;
+}
+
+bool ViewportWidget::focusNextPrevChild(bool next)
+{
+    if (m_activeTool != static_cast<int>(ApplicationController::ToolType::None)) {
+        return false;
+    }
+    return QOpenGLWidget::focusNextPrevChild(next);
+}
+
 void ViewportWidget::onSketchModeStarted(SketchPlane plane)
 {
     m_currentPlane = plane;
 
     m_camera->saveState();
-
-    float targetXRot = m_camera->xRotation();
-    float targetYRot = m_camera->yRotation();
-    switch (plane) {
-        case SketchPlane::XY: // Top view
-            targetXRot = 90 * 16;
-            targetYRot = 0;
-            break;
-        case SketchPlane::XZ: // Front view
-            targetXRot = 0;
-            targetYRot = 0;
-            break;
-        case SketchPlane::YZ: // Right view
-            targetXRot = 0;
-            targetYRot = -90 * 16;
-            break;
-        case SketchPlane::NONE:
-            break;
-    }
-
-    auto* animGroup = new QParallelAnimationGroup(this);
-
-    auto* xRotAnim = new QPropertyAnimation(m_camera, "xRotation");
-    xRotAnim->setDuration(300);
-    xRotAnim->setStartValue(m_camera->xRotation());
-    xRotAnim->setEndValue(targetXRot);
-    xRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
-    animGroup->addAnimation(xRotAnim);
-
-    auto* yRotAnim = new QPropertyAnimation(m_camera, "yRotation");
-    yRotAnim->setDuration(300);
-    yRotAnim->setStartValue(m_camera->yRotation());
-    yRotAnim->setEndValue(targetYRot);
-    yRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
-    animGroup->addAnimation(yRotAnim);
-
-    auto* panXAnim = new QPropertyAnimation(m_camera, "panX");
-    panXAnim->setDuration(300);
-    panXAnim->setStartValue(m_camera->panX());
-    panXAnim->setEndValue(0.0f);
-    panXAnim->setEasingCurve(QEasingCurve::InOutQuad);
-    animGroup->addAnimation(panXAnim);
-
-    auto* panYAnim = new QPropertyAnimation(m_camera, "panY");
-    panYAnim->setDuration(300);
-    panYAnim->setStartValue(m_camera->panY());
-    panYAnim->setEndValue(0.0f);
-    panYAnim->setEasingCurve(QEasingCurve::InOutQuad);
-    animGroup->addAnimation(panYAnim);
-
-    auto* zoomAnim = new QPropertyAnimation(m_camera, "zoom");
-    zoomAnim->setDuration(300);
-    zoomAnim->setStartValue(m_camera->zoom());
-    zoomAnim->setEndValue(-20.0f);
-    zoomAnim->setEasingCurve(QEasingCurve::InOutQuad);
-    animGroup->addAnimation(zoomAnim);
-
-    animGroup->start(QAbstractAnimation::DeleteWhenStopped);
+    m_camera->animateToPlaneView(static_cast<int>(plane));
 }
 
 void ViewportWidget::onPlaneSelectionModeStarted()
@@ -555,50 +390,14 @@ void ViewportWidget::onPlaneSelectionModeStarted()
 
 void ViewportWidget::onSketchModeEnded()
 {
-    auto* animGroup = new QParallelAnimationGroup(this);
+    m_camera->animateRestoreState();
+}
 
-    auto* xRotAnim = new QPropertyAnimation(m_camera, "xRotation");
-    xRotAnim->setDuration(300);
-    xRotAnim->setStartValue(m_camera->xRotation());
-    xRotAnim->setEndValue(m_camera->savedXRot());
-    xRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
-    animGroup->addAnimation(xRotAnim);
-
-    auto* yRotAnim = new QPropertyAnimation(m_camera, "yRotation");
-    yRotAnim->setDuration(300);
-    yRotAnim->setStartValue(m_camera->yRotation());
-    yRotAnim->setEndValue(m_camera->savedYRot());
-    yRotAnim->setEasingCurve(QEasingCurve::InOutQuad);
-    animGroup->addAnimation(yRotAnim);
-
-    auto* panXAnim = new QPropertyAnimation(m_camera, "panX");
-    panXAnim->setDuration(300);
-    panXAnim->setStartValue(m_camera->panX());
-    panXAnim->setEndValue(m_camera->savedPanX());
-    panXAnim->setEasingCurve(QEasingCurve::InOutQuad);
-    animGroup->addAnimation(panXAnim);
-
-    auto* panYAnim = new QPropertyAnimation(m_camera, "panY");
-    panYAnim->setDuration(300);
-    panYAnim->setStartValue(m_camera->panY());
-    panYAnim->setEndValue(m_camera->savedPanY());
-    panYAnim->setEasingCurve(QEasingCurve::InOutQuad);
-    animGroup->addAnimation(panYAnim);
-
-    auto* zoomAnim = new QPropertyAnimation(m_camera, "zoom");
-    zoomAnim->setDuration(300);
-    zoomAnim->setStartValue(m_camera->zoom());
-    zoomAnim->setEndValue(m_camera->savedZoom());
-    zoomAnim->setEasingCurve(QEasingCurve::InOutQuad);
-    animGroup->addAnimation(zoomAnim);
-
-    connect(animGroup, &QParallelAnimationGroup::finished, this, [this]() {
+void ViewportWidget::onRestoreStateAnimationFinished()
+{
     // Return to showing the base XY grid when not in a sketch
     m_currentPlane = SketchPlane::XY;
     update();
-    });
-
-    animGroup->start(QAbstractAnimation::DeleteWhenStopped);
 }
 
 QVector3D ViewportWidget::project(const QVector3D& worldCoord, const QMatrix4x4& modelView, const QMatrix4x4& projection, const QRect& viewport)
@@ -616,43 +415,19 @@ QVector3D ViewportWidget::project(const QVector3D& worldCoord, const QMatrix4x4&
     return QVector3D(winX, winY, (ndc.z() + 1.0) / 2.0);
 }
 
-void ViewportWidget::drawAxisLabels(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection)
-{
-    painter.setPen(Qt::white);
-    painter.setFont(QFont("Arial", 10));
-
-    const int range = 50;
-    const int step = 5;
-
-    auto drawLabelsForAxis = [&](int axis_idx) {
-        for (int i = -range; i <= range; i += step) {
-            if (i == 0) continue;
-            QVector3D worldCoord;
-            worldCoord[axis_idx] = i;
-
-            QVector3D screenPos = project(worldCoord, modelView, projection, rect());
-            if (screenPos.z() < 1.0f) { // Not clipped
-                painter.drawText(screenPos.toPoint(), QString::number(i));
-            }
-        }
-    };
-
-    if (m_currentPlane == SketchPlane::XY) {
-        drawLabelsForAxis(0); // X
-        drawLabelsForAxis(2); // Y
-    } else if (m_currentPlane == SketchPlane::XZ) {
-        drawLabelsForAxis(0); // X
-        drawLabelsForAxis(1); // Z
-    } else if (m_currentPlane == SketchPlane::YZ) {
-        drawLabelsForAxis(1); // Y
-        drawLabelsForAxis(2); // Z
-    }
-}
-
 void ViewportWidget::onActiveToolChanged(int tool)
 {
+    if (m_activeSketchTool) {
+        m_activeSketchTool->deactivate();
+        m_activeSketchTool = nullptr;
+    }
+
     m_activeTool = tool;
-    m_isDefiningLine = false;
+
+    if (m_sketchTools.contains(tool)) {
+        m_activeSketchTool = m_sketchTools.value(tool);
+        m_activeSketchTool->activate();
+    }
 
     if (tool == static_cast<int>(ApplicationController::ToolType::None)) {
         unsetCursor();
@@ -744,10 +519,9 @@ void ViewportWidget::drawSketch(const SketchFeature* sketch)
 {
     glDisable(GL_DEPTH_TEST);
     glLineWidth(2.0f);
-    glPointSize(5.0f);
 
     QVector<GLfloat> lineVertices;
-    QMap<gp_Pnt, int, PntComparator> vertexCounts;
+    std::map<gp_Pnt, int, PntComparator> vertexCounts;
 
     for (const auto& obj : sketch->objects()) {
         if (obj->type() == SketchObject::ObjectType::Line) {
@@ -759,14 +533,69 @@ void ViewportWidget::drawSketch(const SketchFeature* sketch)
 
             vertexCounts[start]++;
             vertexCounts[end]++;
-        }
+        } else if (obj->type() == SketchObject::ObjectType::Circle) {
+            auto circle = static_cast<const SketchCircle*>(obj);
+            const auto& center = circle->center();
+            double radius = circle->radius();
+            QVector3D centerPos(center.X(), center.Y(), center.Z());
+
+            const int numSegments = 64;
+            QVector3D u_axis, v_axis;
+            switch (sketch->plane()) {
+                case SketchFeature::SketchPlane::XY:
+                    u_axis = QVector3D(1, 0, 0);
+                    v_axis = QVector3D(0, 0, 1);
+                    break;
+                case SketchFeature::SketchPlane::XZ:
+                    u_axis = QVector3D(1, 0, 0);
+                    v_axis = QVector3D(0, 1, 0);
+                    break;
+                case SketchFeature::SketchPlane::YZ:
+                    u_axis = QVector3D(0, 1, 0);
+                    v_axis = QVector3D(0, 0, 1);
+                    break;
             }
 
-    QVector<GLfloat> pointVertices;
-    for (auto it = vertexCounts.constBegin(); it != vertexCounts.constEnd(); ++it) {
-        if (it.value() == 1) {
-            const gp_Pnt& p = it.key();
-            pointVertices << p.X() << p.Y() << p.Z();
+            for (int i = 0; i < numSegments; ++i) {
+                double angle1 = 2.0 * M_PI * double(i) / double(numSegments);
+                QVector3D p1 = centerPos + radius * (cos(angle1) * u_axis + sin(angle1) * v_axis);
+
+                double angle2 = 2.0 * M_PI * double(i + 1) / double(numSegments);
+                QVector3D p2 = centerPos + radius * (cos(angle2) * u_axis + sin(angle2) * v_axis);
+
+                lineVertices << p1.x() << p1.y() << p1.z();
+                lineVertices << p2.x() << p2.y() << p2.z();
+            }
+        } else if (obj->type() == SketchObject::ObjectType::Rectangle) {
+            auto rect = static_cast<const SketchRectangle*>(obj);
+            const auto& p1 = rect->corner1();
+            const auto& p3 = rect->corner2();
+
+            gp_Pnt p2, p4;
+            if (sketch->plane() == SketchFeature::SketchPlane::XY) {
+                p2.SetCoord(p3.X(), p1.Y(), p1.Z());
+                p4.SetCoord(p1.X(), p1.Y(), p3.Z());
+            } else if (sketch->plane() == SketchFeature::SketchPlane::XZ) {
+                p2.SetCoord(p3.X(), p1.Y(), p1.Z());
+                p4.SetCoord(p1.X(), p3.Y(), p1.Z());
+            } else if (sketch->plane() == SketchFeature::SketchPlane::YZ) {
+                p2.SetCoord(p1.X(), p3.Y(), p1.Z());
+                p4.SetCoord(p1.X(), p1.Y(), p3.Z());
+            }
+
+            lineVertices << p1.X() << p1.Y() << p1.Z();
+            lineVertices << p2.X() << p2.Y() << p2.Z();
+            lineVertices << p2.X() << p2.Y() << p2.Z();
+            lineVertices << p3.X() << p3.Y() << p3.Z();
+            lineVertices << p3.X() << p3.Y() << p3.Z();
+            lineVertices << p4.X() << p4.Y() << p4.Z();
+            lineVertices << p4.X() << p4.Y() << p4.Z();
+            lineVertices << p1.X() << p1.Y() << p1.Z();
+
+            vertexCounts[p1] += 2;
+            vertexCounts[p2] += 2;
+            vertexCounts[p3] += 2;
+            vertexCounts[p4] += 2;
         }
     }
 
@@ -775,16 +604,137 @@ void ViewportWidget::drawSketch(const SketchFeature* sketch)
 
     if (!lineVertices.isEmpty()) {
         m_vbo.allocate(lineVertices.constData(), lineVertices.size() * sizeof(GLfloat));
+        m_shaderProgram->enableAttributeArray(0);
+        m_shaderProgram->setAttributeBuffer(0, GL_FLOAT, 0, 3, 0);
+        m_shaderProgram->disableAttributeArray(1);
         glDrawArrays(GL_LINES, 0, lineVertices.size() / 3);
     }
-    if (!pointVertices.isEmpty()) {
-        glEnable(GL_POINT_SMOOTH);
-        glEnable(GL_BLEND);
-        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-        m_vbo.allocate(pointVertices.constData(), pointVertices.size() * sizeof(GLfloat));
-        glDrawArrays(GL_POINTS, 0, pointVertices.size() / 3);
-        glDisable(GL_BLEND);
-        glDisable(GL_POINT_SMOOTH);
+
+    QVector<gp_Pnt> unattachedVertices;
+    for (const auto& pair : vertexCounts) {
+        if (pair.second == 1) {
+            unattachedVertices.append(pair.first);
+        }
+    }
+
+    if (!unattachedVertices.isEmpty()) {
+        const float radius = 0.004f * -m_camera->uiCameraDistance();
+        const int numSegments = 16;
+        QMatrix4x4 invModelView = m_camera->modelViewMatrix().inverted();
+        QVector3D rightVec = invModelView.column(0).toVector3D();
+        QVector3D upVec = invModelView.column(1).toVector3D();
+
+        QVector<GLfloat> circleFillVertices;
+        QVector<GLfloat> circleOutlineVertices;
+
+        for (const auto& centerPnt : unattachedVertices) {
+            QVector3D center(centerPnt.X(), centerPnt.Y(), centerPnt.Z());
+
+            circleFillVertices << center.x() << center.y() << center.z(); // Center vertex for fan
+
+            QVector3D firstCircumferencePoint;
+            for (int i = 0; i < numSegments; ++i) {
+                float angle = (2.0f * M_PI * float(i)) / float(numSegments);
+                QVector3D p = center + radius * (cos(angle) * rightVec + sin(angle) * upVec);
+                if (i == 0) {
+                    firstCircumferencePoint = p;
+                }
+                circleFillVertices << p.x() << p.y() << p.z();
+                circleOutlineVertices << p.x() << p.y() << p.z();
+            }
+            circleFillVertices << firstCircumferencePoint.x() << firstCircumferencePoint.y() << firstCircumferencePoint.z();
+        }
+
+        // Draw fills
+        m_shaderProgram->setUniformValue(m_colorLoc, QVector4D(0.2f, 0.3f, 0.3f, 1.0f));
+        m_vbo.allocate(circleFillVertices.constData(), circleFillVertices.size() * sizeof(GLfloat));
+        const int vertsPerFan = numSegments + 2;
+        for (size_t i = 0; i < unattachedVertices.size(); ++i) {
+            glDrawArrays(GL_TRIANGLE_FAN, i * vertsPerFan, vertsPerFan);
+        }
+
+        // Draw outlines
+        m_shaderProgram->setUniformValue(m_colorLoc, QVector4D(1.0f, 1.0f, 1.0f, 1.0f));
+        m_vbo.allocate(circleOutlineVertices.constData(), circleOutlineVertices.size() * sizeof(GLfloat));
+        const int vertsPerLoop = numSegments;
+        for (size_t i = 0; i < unattachedVertices.size(); ++i) {
+            glDrawArrays(GL_LINE_LOOP, i * vertsPerLoop, vertsPerLoop);
+        }
+    }
+
+    // Draw faces
+    if (!sketch->shape().IsNull()) {
+        glDisable(GL_CULL_FACE);
+        BRepMesh_IncrementalMesh(sketch->shape(), 0.1, Standard_False, 0.5, Standard_True); // Linear deflection, compute normals
+
+        QVector<GLfloat> faceData;
+        TopExp_Explorer explorer(sketch->shape(), TopAbs_FACE);
+        for (; explorer.More(); explorer.Next()) {
+            TopoDS_Face face = TopoDS::Face(explorer.Current());
+            TopLoc_Location location;
+            Handle(Poly_Triangulation) triangulation = BRep_Tool::Triangulation(face, location);
+
+            if (!triangulation.IsNull()) {
+                gp_Trsf locTrsf = location.Transformation();
+
+                if (triangulation->HasNormals()) {
+                    for (int i = 1; i <= triangulation->NbTriangles(); ++i) {
+                        const Poly_Triangle& triangle = triangulation->Triangle(i);
+                        for (int j = 1; j <= 3; ++j) {
+                            int nodeIdx = triangle.Value(j);
+                            gp_Pnt p = triangulation->Node(nodeIdx).Transformed(location);
+                            gp_Dir n = triangulation->Normal(nodeIdx);
+                            n.Transform(locTrsf);
+
+                            if (face.Orientation() == TopAbs_REVERSED) {
+                                n.Reverse();
+                            }
+                            faceData << p.X() << p.Y() << p.Z();
+                            faceData << n.X() << n.Y() << n.Z();
+                        }
+                    }
+                } else {
+                    for (int i = 1; i <= triangulation->NbTriangles(); ++i) {
+                        const Poly_Triangle& triangle = triangulation->Triangle(i);
+                        gp_Pnt p1 = triangulation->Node(triangle.Value(1)).Transformed(location);
+                        gp_Pnt p2 = triangulation->Node(triangle.Value(2)).Transformed(location);
+                        gp_Pnt p3 = triangulation->Node(triangle.Value(3)).Transformed(location);
+
+                        QVector3D v1(p1.X(), p1.Y(), p1.Z());
+                        QVector3D v2(p2.X(), p2.Y(), p2.Z());
+                        QVector3D v3(p3.X(), p3.Y(), p3.Z());
+                        QVector3D faceNormal = QVector3D::crossProduct(v2 - v1, v3 - v1).normalized();
+                        if (face.Orientation() == TopAbs_REVERSED) {
+                            faceNormal = -faceNormal;
+                        }
+                        faceData << p1.X() << p1.Y() << p1.Z() << faceNormal.x() << faceNormal.y() << faceNormal.z();
+                        faceData << p2.X() << p2.Y() << p2.Z() << faceNormal.x() << faceNormal.y() << faceNormal.z();
+                        faceData << p3.X() << p3.Y() << p3.Z() << faceNormal.x() << faceNormal.y() << faceNormal.z();
+                    }
+                }
+            }
+        }
+
+        if (!faceData.isEmpty()) {
+            m_litShaderProgram->bind();
+            m_litShaderProgram->setUniformValue(m_litProjMatrixLoc, projection);
+            m_litShaderProgram->setUniformValue(m_litMvMatrixLoc, m_camera->modelViewMatrix());
+            m_litShaderProgram->setUniformValue(m_litNormalMatrixLoc, m_camera->modelViewMatrix().normalMatrix());
+
+            m_vbo.bind();
+            m_vbo.allocate(faceData.constData(), faceData.size() * sizeof(GLfloat));
+
+            m_litShaderProgram->enableAttributeArray(0);
+            m_litShaderProgram->setAttributeBuffer(0, GL_FLOAT, 0, 3, 6 * sizeof(GLfloat));
+            m_litShaderProgram->enableAttributeArray(1);
+            m_litShaderProgram->setAttributeBuffer(1, GL_FLOAT, 3 * sizeof(GLfloat), 3, 6 * sizeof(GLfloat));
+
+            glDrawArrays(GL_TRIANGLES, 0, faceData.size() / 6);
+            m_litShaderProgram->disableAttributeArray(1);
+            m_shaderProgram->bind(); // rebind simple shader for subsequent draws
+            m_shaderProgram->setAttributeBuffer(0, GL_FLOAT, 0, 3, 0);
+        }
+        glEnable(GL_CULL_FACE);
     }
 
     glEnable(GL_DEPTH_TEST);
@@ -792,8 +742,8 @@ void ViewportWidget::drawSketch(const SketchFeature* sketch)
 
 void ViewportWidget::initShaders()
 {
+    // Simple shader for lines and grids
     m_shaderProgram = new QOpenGLShaderProgram(this);
-
     if (!m_shaderProgram->addShaderFromSourceFile(QOpenGLShader::Vertex, ":/shaders/simple.vert")) {
         qCritical() << "Vertex shader compilation failed:" << m_shaderProgram->log();
         return;
@@ -806,10 +756,27 @@ void ViewportWidget::initShaders()
         qCritical() << "Shader program linking failed:" << m_shaderProgram->log();
         return;
     }
-
     m_projMatrixLoc = m_shaderProgram->uniformLocation("projectionMatrix");
     m_mvMatrixLoc = m_shaderProgram->uniformLocation("modelViewMatrix");
     m_colorLoc = m_shaderProgram->uniformLocation("objectColor");
+
+    // Lit shader for faces
+    m_litShaderProgram = new QOpenGLShaderProgram(this);
+    if (!m_litShaderProgram->addShaderFromSourceFile(QOpenGLShader::Vertex, ":/shaders/lit.vert")) {
+        qCritical() << "Lit vertex shader compilation failed:" << m_litShaderProgram->log();
+        return;
+    }
+    if (!m_litShaderProgram->addShaderFromSourceFile(QOpenGLShader::Fragment, ":/shaders/lit.frag")) {
+        qCritical() << "Lit fragment shader compilation failed:" << m_litShaderProgram->log();
+        return;
+    }
+    if (!m_litShaderProgram->link()) {
+        qCritical() << "Lit shader program linking failed:" << m_litShaderProgram->log();
+        return;
+    }
+    m_litProjMatrixLoc = m_litShaderProgram->uniformLocation("projectionMatrix");
+    m_litMvMatrixLoc = m_litShaderProgram->uniformLocation("modelViewMatrix");
+    m_litNormalMatrixLoc = m_litShaderProgram->uniformLocation("normalMatrix");
 }
 
 void ViewportWidget::drawSelectionPlanes()
@@ -824,6 +791,9 @@ void ViewportWidget::drawSelectionPlanes()
     glDisable(GL_DEPTH_TEST);
 
     m_vbo.bind();
+    m_shaderProgram->enableAttributeArray(0);
+    m_shaderProgram->setAttributeBuffer(0, GL_FLOAT, 0, 3, 0);
+    m_shaderProgram->disableAttributeArray(1);
     QVector<GLfloat> vertices;
 
     auto drawPlane = [&](const QVector<GLfloat>& quadVerts, bool highlighted) {

src/ViewportWidget.h

@@ -20,6 +20,8 @@ class Document;
 class FeatureBrowser;
 class SketchFeature;
 class Camera;
+class SketchTool;
+class Snapping;
 
 class ViewportWidget : public QOpenGLWidget, protected QOpenGLFunctions
 {
@@ -38,6 +40,27 @@ public:
 
     void setDocument(Document* document);
 
+    QVector3D project(const QVector3D& worldCoord, const QMatrix4x4& modelView, const QMatrix4x4& projection, const QRect& viewport);
+    QVector3D unproject(const QPoint& screenPos, SketchPlane plane);
+    QOpenGLShaderProgram* shaderProgram() { return m_shaderProgram; }
+    QOpenGLBuffer& vbo() { return m_vbo; }
+    int colorLoc() const { return m_colorLoc; }
+    Camera* camera() const { return m_camera; }
+    Document* document() const { return m_document; }
+    SketchPlane currentPlane() const { return m_currentPlane; }
+    const QPoint& currentMousePos() const { return m_currentMousePos; }
+    bool isSnappingOrigin() const;
+    bool isSnappingVertex() const;
+    const gp_Pnt& snapVertex() const;
+    int activeTool() const { return m_activeTool; }
+    bool isSnappingHorizontal() const { return m_isSnappingHorizontal; }
+    bool isSnappingVertical() const { return m_isSnappingVertical; }
+    void setSnappingHorizontal(bool snapping);
+    void setSnappingVertical(bool snapping);
+
+    void addLine(const gp_Pnt& start, const gp_Pnt& end);
+    void deactivateActiveTool();
+
 public slots:
     void onSketchModeStarted(SketchPlane plane);
     void onSketchModeEnded();
@@ -46,30 +69,35 @@ public slots:
 
 signals:
     void lineAdded(const gp_Pnt& start, const gp_Pnt& end);
+    void rectangleAdded(const gp_Pnt& corner1, const gp_Pnt& corner2);
+    void circleAdded(const gp_Pnt& center, double radius);
     void planeSelected(SketchPlane plane);
     void toolDeactivated();
 
+private slots:
+    void onRestoreStateAnimationFinished();
+
 protected:
     void initializeGL() override;
     void paintGL() override;
     void resizeGL(int w, int h) override;
 
     void mousePressEvent(QMouseEvent *event) override;
+    void mouseReleaseEvent(QMouseEvent *event) override;
     void mouseMoveEvent(QMouseEvent *event) override;
     void wheelEvent(QWheelEvent *event) override;
     void keyPressEvent(QKeyEvent *event) override;
+    bool focusNextPrevChild(bool next) override;
 
 private:
     void initShaders();
-    QVector3D project(const QVector3D& worldCoord, const QMatrix4x4& modelView, const QMatrix4x4& projection, const QRect& viewport);
-    QVector3D unproject(const QPoint& screenPos, SketchPlane plane);
-    void drawAxisLabels(QPainter& painter, const QMatrix4x4& modelView, const QMatrix4x4& projection);
     void drawSketch(const SketchFeature* sketch);
     void drawSelectionPlanes();
     ViewportWidget::SketchPlane checkPlaneSelection(const QPoint& screenPos);
 
     QMatrix4x4 projection;
     QOpenGLShaderProgram* m_shaderProgram = nullptr;
+    QOpenGLShaderProgram* m_litShaderProgram = nullptr;
     QOpenGLVertexArrayObject m_vao;
     QOpenGLBuffer m_vbo;
 
@@ -77,6 +105,11 @@ private:
     int m_projMatrixLoc = -1;
     int m_mvMatrixLoc = -1;
     int m_colorLoc = -1;
+
+    // Lit shader uniform locations
+    int m_litProjMatrixLoc = -1;
+    int m_litMvMatrixLoc = -1;
+    int m_litNormalMatrixLoc = -1;
     Camera* m_camera = nullptr;
     ViewCube* m_viewCube;
     SketchGrid* m_sketchGrid = nullptr;
@@ -88,19 +121,15 @@ private:
     SketchPlane m_highlightedPlane = SketchPlane::NONE;
 
     int m_activeTool = 0;
-    bool m_isDefiningLine = false;
-    gp_Pnt m_firstLinePoint;
+    SketchTool* m_activeSketchTool = nullptr;
+    QMap<int, SketchTool*> m_sketchTools;
     QPoint m_currentMousePos;
-    bool m_isSnappingOrigin = false;
-    bool m_isSnappingVertex = false;
-    gp_Pnt m_snapVertex;
+    Snapping* m_snapping = nullptr;
     bool m_isSnappingHorizontal = false;
     bool m_isSnappingVertical = false;
 
     QMap<int, QSvgRenderer*> m_toolIcons;
     QSvgRenderer* m_cursorRenderer = nullptr;
-
-    QPoint lastPos;
 };
 
 #endif // VIEWPORTWIDGET_H

src/shaders/lit.frag

@@ -0,0 +1,33 @@
+#version 330 core
+out vec4 FragColor;
+
+in vec3 FragPos;
+in vec3 Normal;
+
+void main()
+{
+    vec3 viewPos = vec3(0.0, 0.0, 0.0); // View position is origin in view space
+    vec3 lightPos = vec3(0.0, 10.0, 5.0); // Light position in view space
+    vec3 lightColor = vec3(1.0, 1.0, 1.0);
+    vec3 objectColor = vec3(0.5, 0.5, 1.0);
+
+    // Ambient
+    float ambientStrength = 0.3;
+    vec3 ambient = ambientStrength * lightColor;
+
+    // Diffuse
+    vec3 norm = normalize(Normal);
+    vec3 lightDir = normalize(lightPos - FragPos);
+    float diff = max(dot(norm, lightDir), 0.0);
+    vec3 diffuse = diff * lightColor;
+
+    // Specular
+    float specularStrength = 0.5;
+    vec3 viewDir = normalize(viewPos - FragPos);
+    vec3 reflectDir = reflect(-lightDir, norm);
+    float spec = pow(max(dot(viewDir, reflectDir), 0.0), 32);
+    vec3 specular = specularStrength * spec * lightColor;
+
+    vec3 result = (ambient + diffuse + specular) * objectColor;
+    FragColor = vec4(result, 1.0);
+}

src/shaders/lit.vert

@@ -0,0 +1,17 @@
+#version 330 core
+layout (location = 0) in vec3 aPos;
+layout (location = 1) in vec3 aNormal;
+
+out vec3 FragPos;
+out vec3 Normal;
+
+uniform mat4 modelViewMatrix;
+uniform mat4 projectionMatrix;
+uniform mat3 normalMatrix;
+
+void main()
+{
+    FragPos = vec3(modelViewMatrix * vec4(aPos, 1.0));
+    Normal = normalMatrix * aNormal;
+    gl_Position = projectionMatrix * modelViewMatrix * vec4(aPos, 1.0);
+}

src/shaders/texture.frag

@@ -5,8 +5,10 @@ out vec4 FragColor;
 in vec2 TexCoord;
 
 uniform sampler2D texture_diffuse1;
+uniform float opacity;
 
 void main()
 {
-    FragColor = texture(texture_diffuse1, TexCoord);
+    vec4 texColor = texture(texture_diffuse1, TexCoord);
+    FragColor = vec4(texColor.rgb, texColor.a * opacity);
 }