OneCAD

⚠️ Development Notice: This project is under active development and contains multiple known bugs. Not all features work correctly — use at your own risk.

⚠️ VibeCoding Alert: Full codebase generated with AI. Project in active development—manual review & validation required.

Overview

OneCAD is a free, open-source 3D CAD application for makers and hobbyists. Sketch 2D geometry, add constraints, create faces, then extrude to 3D. Inspired by Shapr3D, built with C++20 + Qt6 + OpenCASCADE.

Current Status: Phase 3 ~85% Complete

• ✅ Full sketching engine (~10,000 LOC)
• ✅ 15 constraint types with automatic inference
• ✅ PlaneGCS solver integration (1450 LOC)
• ✅ All core modeling operations (Extrude, Revolve, Fillet, Chamfer, Shell, Boolean)
• ✅ Complete I/O layer (Save/Load, STEP import/export)
• ✅ Light/Dark themes, ViewCube, StartOverlay
• 🚀 ~41,000 LOC total across 170 files

Implementation Matrix

Feature Area	Status	Notes
Sketching engine + constraints	✅ Complete	7 tools, 15 constraints, PlaneGCS solver, loop detection
Selection & picking	✅ Complete	Deep select, click cycling, mesh-based 3D picking
Rendering (Shaded + Edges)	✅ Complete	BodyRenderer + SceneMeshStore + preview meshes
Adaptive Grid3D	✅ Complete	Pixel-targeted spacing
Extrude + Push/Pull	✅ Complete	SketchRegion + Face input, draft angle, auto-boolean (500 LOC)
Revolve	✅ Complete	Profile+Axis selection, drag interaction, boolean mode (430 LOC)
Boolean (Union/Cut/Intersect)	✅ Complete	BRepAlgoAPI + ModifyBodyCommand + smart mode detection
Fillet/Chamfer	✅ Complete	Combined tool, drag mode switching, edge chaining (408 LOC)
Shell	⚠️ Partial	Single-face working; multi-face UI wiring pending (312 LOC)
Command + Undo/Redo	✅ Complete	Full CommandProcessor, 9 commands, transactions
ViewCube	✅ Complete	3D navigation widget (537 LOC)
Native save/load (.onecad)	✅ Complete	ZIP package, BREP cache, history serialization
STEP I/O	✅ Complete	Import/export pipeline (250 LOC)
Light/Dark themes	✅ Complete	ThemeManager (885 LOC)
Start overlay	✅ Complete	Project browser with thumbnails
Patterns (Linear/Circular)	⏳ Planned	Not started
Feature history UI	⏳ Planned	HistoryPanel not implemented
Command Search	⏳ Planned	Cmd+K palette
Camera inertia	⏳ Planned	Physics not implemented

Technology Stack

• C++20 — Modern C++ (CMake enforced)
• Qt6 — GUI framework
• OpenCASCADE (OCCT) — Geometric modeling kernel
• Eigen3 — Linear algebra
• PlaneGCS — Constraint solver
• OpenGL 4.1 Core — Rendering

Platform Support (v1.0)

• macOS 14+ (Apple Silicon native) — primary target
• Intel Mac — v2.0 planned
• Linux/Windows — future consideration

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Quick Links

• 📖 DEVELOPMENT.md — Setup, architecture, best practices, debugging
• 📋 docs/SPECIFICATION.md — Full product requirements (3700+ lines)
• 🗺️ docs/PHASES.md — Implementation roadmap
• 🔧 docs/ELEMENT_MAP.md — Topological naming system
• 🤖 .github/copilot-instructions.md — AI development guidelines

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Key Features

Sketching Engine ✅ Complete

• 7 tools: Line, Arc, Circle, Rectangle, Ellipse, Mirror, Trim (~2,000 LOC)
• 5 entity types: Point, Line, Arc, Circle, Ellipse (with construction geometry toggle)
• Constraint solver: PlaneGCS with 15 constraint types (1450 LOC)
• Automatic inference: AutoConstrainer with 7 inference rules (1091 LOC)
• Smart snapping: SnapManager with 8 snap types, 2mm radius (1166 LOC)
• Loop detection: LoopDetector with DFS cycles + hole detection (1887 LOC)
• Face builder: OCCT bridge with wire repair (719 LOC)

3D Modeling ✅ Core Complete (~85%)

• ✅ Extrude + Push/Pull: SketchRegion + Face input, draft angle, auto-boolean (500 LOC)
• ✅ Revolve: Profile+Axis, drag interaction, boolean mode (430 LOC)
• ✅ Boolean ops: Union/Cut/Intersect with smart mode detection (130 LOC)
• ✅ Fillet/Chamfer: Combined tool, variable radius, edge chaining (408 LOC)
• ✅ Shell: Hollow solid creation (312 LOC, single-face working)
• ⏳ Patterns: Linear/Circular arrays (not started)

File I/O ✅ Complete

• ✅ Native format (.onecad): ZIP package with BREP cache + history (~2,400 LOC)
• ✅ STEP import/export: Industry standard exchange (250 LOC)
• ✅ Dual package backend: QuaZip primary, system zip fallback

User Experience

• Zero-friction startup: Open to blank document or project browser
• Visual feedback: Blue/green constraint states (DOF tracking)
• Light/Dark themes: Full UI theming (885 LOC)
• Real-time preview: All modeling operations with drag-to-commit
• ViewCube: 3D navigation widget (537 LOC)
• Undo/redo: Full transaction support with 9 commands

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Repository Structure

OneCAD/
├── src/                      # ~41,000 LOC across 170 files
│   ├── app/                  # Application lifecycle (25 files, ~3,000 LOC)
│   │   ├── commands/         # 9 commands (Add/Delete/Modify/Rename Body/Sketch, Visibility)
│   │   ├── document/         # Document model, OperationRecord
│   │   └── selection/        # SelectionManager with deep select
│   ├── core/                 # Core geometry (~13,000 LOC)
│   │   ├── sketch/           # 48 files - entities, tools, constraints, solver
│   │   ├── loop/             # LoopDetector, FaceBuilder, AdjacencyGraph
│   │   └── modeling/         # BooleanOperation, EdgeChainer
│   ├── kernel/               # ElementMap - topological naming (990 LOC)
│   ├── render/               # Camera3D, Grid3D, BodyRenderer (~2,500 LOC)
│   ├── io/                   # File I/O (~2,400 LOC)
│   │   ├── step/             # STEP import/export
│   │   └── ...               # OneCADFileIO, DocumentIO, ZipPackage
│   └── ui/                   # User interface (~13,000 LOC)
│       ├── viewport/         # Viewport (2921 LOC) + RenderDebugPanel
│       ├── tools/            # Extrude, Revolve, Fillet, Shell tools
│       ├── navigator/        # ModelNavigator
│       ├── viewcube/         # ViewCube navigation
│       ├── theme/            # ThemeManager
│       └── start/            # StartOverlay, ProjectTile
├── tests/                    # Prototype executables
├── docs/                     # SPECIFICATION.md (3700+), PHASES.md
├── third_party/              # PlaneGCS (42MB static lib)
└── resources/                # Icons, shaders

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Contributing

For Developers

Start here: DEVELOPMENT.md contains:

• ✅ Environment setup (macOS, Linux)
• ✅ Build instructions
• ✅ Architecture overview
• ✅ Code best practices (C++20, Qt, naming conventions)
• ✅ Guide to key systems (sketch engine, solver, rendering)
• ✅ Common development tasks (adding tools, constraints, debugging)
• ✅ Testing strategy (prototype executables)

Quick Build

# Clone repository
git clone https://github.com/yourusername/OneCAD.git
cd OneCAD

# See DEVELOPMENT.md for full setup instructions

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License

MIT or Apache 2.0 (to be determined)

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Acknowledgments

• OpenCASCADE (OCCT): Geometric modeling kernel
• PlaneGCS: Constraint solver
• Qt6: GUI framework
• Eigen3: Linear algebra library
• Inspired by Shapr3D, FreeCAD, SketchUp

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Project Status

Phase	Status	Progress
Phase 1 Foundation	✅ Complete	~98%
↳ 1.1 Project & Rendering	✅	~98%
↳ 1.2 OCCT Kernel	Partial	~50%
↳ 1.3 Topological Naming	✅	~95%
↳ 1.4 Command & Document	✅	100%
Phase 2 Sketching	✅ Complete	100%
Phase 3 Solid Modeling	🚀 In Progress	~85%
↳ 3.1 I/O Foundation	✅ Complete	100%
↳ 3.2 Parametric Engine	Partial	~25%
↳ 3.3 Modeling Operations	✅ Complete	100%
↳ 3.4 Pattern Operations	Not Started	0%
↳ 3.5 UI Polish	In Progress	~40%
Phase 4 Advanced Modeling	Partial	~10%
Phase 5 Optimization	📋 Planned	0%

See docs/PHASES.md for detailed roadmap.

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Want to contribute? Check out DEVELOPMENT.md to get started!