unnamed-cad-software/CONTEXT.md

OpenCAD Context

Project Goal: To build an open source cross-platform Fusion 360 3D CAD clone using C++, Qt, and OpenGL.

Features should be as close to Fusion 360 as possible.

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Architecture

The application is structured using a Model-View-Controller (MVC) architecture to ensure a clear separation of concerns, making the codebase easier to maintain and extend.

• Model: This layer represents the application's data and business logic. It knows nothing about the user interface.

  • Document: Manages the collection of all features.
  • Feature, SketchFeature: Represent individual components or operations in the CAD model.

• View: This layer is responsible for displaying the data from the Model and capturing user input. It should be as "dumb" as possible, delegating all actions to the Controller.

  • MainWindow: The main application window, toolbars, and menus.
  • ViewportWidget: The 3D OpenGL viewport for rendering the model.
  • FeatureBrowser: The UI component that lists the features in the document.

• Controller: This layer acts as the intermediary between the Model and the View. It contains the application's core logic.

  • ApplicationController: The "brains" of the application. It is created in main() and passed to the UI. It responds to user actions from the View, manipulates the Model, and uses signals and slots to notify the View of any state changes.

Development Log

1 Initial Setup: We created the basic application structure with a MainWindow class. This window was set up with a top toolbar to act as a banner for tools and a central widget area as a placeholder for the 3D viewport. 2 3D Viewport Implementation: We created a ViewportWidget class (inheriting from QOpenGLWidget) to handle 3D rendering. This widget replaced the initial placeholder. To test functionality, we rendered a simple, multi-colored 3D cube in the center of the viewport. 3 Camera Controls: We implemented mouse-based camera controls in the ViewportWidget: • Zoom: Mouse scroll wheel. • Rotate: Middle mouse button drag. • Pan: Shift + Middle mouse button drag. 4 View Cube: We added a view orientation cube (like in Fusion 360) to the top-right corner of the viewport. • The first version used QPainter to draw 2D text labels ("TOP", "FRONT", etc.) over the 3D cube. • We then improved this by rendering the labels as textures directly onto the faces of the 3D view cube, so they rotate with the cube. 5 Refactoring: To improve code organization, all logic related to the view cube (drawing, texturing, and axis lines) was extracted from ViewportWidget into its own dedicated ViewCube class. 6 UI Toolbar: We implemented a tabbed toolbar in the MainWindow to mimic the Fusion 360 UI. • Created "SOLID", "SURFACE", and "TOOLS" tabs. • Added "Create Sketch" and "Extrude" QToolButtons to the "SOLID" tab, complete with custom SVG icons loaded via a Qt resource file (.qrc). 7 Code Cleanup & Bug Fixes: • Removed the initial colorful test cube from the main scene. • Fixed a build error caused by a typo (QMatrix4xá4 instead of QMatrix4x4) that was introduced during the cleanup. • Resolved a Qt6 compatibility issue by replacing a legacy Qt5 OpenGL header include with its modern equivalent. 8 Sketch Creation Workflow: • Implemented a sketch creation dialog that prompts the user to select a plane (XY, XZ, YZ). • The viewport camera automatically orients itself to be normal to the chosen plane. • Created a dedicated SketchGrid class to draw a 2D grid on the active sketch plane, complete with major/minor grid lines, labeled axes, and an origin point. • Fixed a bug where the XY and XZ camera orientations were incorrect. 9 Data Model and File Persistence: • Designed and implemented a feature-based dependency graph model. • Created a base Feature class and a concrete SketchFeature class. • A Document class was created to manage the collection of features (the feature graph). • Implemented JSON serialization for the document, allowing models to be saved to and loaded from disk. • Added "New", "Open", "Save", and "Save As" functionality to the main file menu. 10 Feature Browser UI: • Added a dockable feature browser (tree view) to the left side of the main window. • The browser displays the current document as the root node and lists all features (e.g., "Sketch") as children. • The Document class now uses Qt signals and slots to notify the MainWindow of changes, ensuring the feature browser is always synchronized with the underlying data model. 11 Floating Feature Browser: • Replaced the dockable feature browser with a floating, semi-transparent overlay inside the viewport, mimicking Fusion 360's UI. • The drawing logic was encapsulated into a dedicated FeatureBrowser class to improve modularity. • Position was set to the top-left corner and font size was increased for better visibility. • Fixed a linker error by adding the new FeatureBrowser.cpp source file to the CMakeLists.txt build configuration. 12 View Cube Rendering Fix: • Resolved a rendering glitch where the View Cube appeared transparent on startup by enabling the OpenGL depth test (GL_DEPTH_TEST) and face culling (GL_CULL_FACE) at the beginning of each frame's render cycle. 13 Sketch Mode UI and State Management: • Implemented a dedicated "SKETCH" UI mode. When a sketch is created, the main toolbar tabs are replaced with a single "SKETCH" tab. • Added "Line", "Rectangle", "Circle", and "Save Sketch" tool buttons to the sketch tab, complete with new SVG icons. • Fixed an issue where tool buttons only showed icons; they now display text labels below the icons for clarity. • The sketch grid is now only rendered when in sketch mode. 14 Camera Animation and View Presets: • Implemented smooth camera transitions when entering and exiting sketch mode. The camera animates to a view normal to the sketch plane and animates back to its original position when the sketch is saved. • This was achieved by converting camera parameters into Qt properties and using QPropertyAnimation. • Resolved a C++ build error caused by naming conflicts between camera state member variables and their accessor methods. • The default startup camera view was changed to a standard isometric angle for a better initial perspective.