# Fluency CAD 2.0

A parametric CAD application built on OpenCASCADE Technology (OCCT) with a modern pygfx-based 3D renderer.

## Features

- **OpenCASCADE Geometry Kernel**: Industry-standard BRep geometry with exact precision
- **STEP/IGES Import/Export**: Full support for industry-standard CAD file formats
- **Parametric Sketching**: 2D sketching with constraint solving using CadQuery
- **Boolean Operations**: Union, difference, and intersection
- **Fillet & Chamfer**: Apply edge treatments to solid bodies
- **Modern Renderer**: WebGPU-based rendering with pygfx (smaller footprint than VTK)

## Architecture

```
fluency/
├── src/fluency/
│   ├── geometry/           # Geometry abstraction layer
│   │   └── base.py         # Abstract interfaces
│   ├── geometry_occ/       # OpenCASCADE implementation
│   │   ├── kernel.py       # OCGeometryKernel
│   │   └── sketch.py       # OCCSketch with constraints
│   ├── rendering/          # Rendering abstraction
│   │   ├── base.py         # Abstract renderer
│   │   └── pygfx_renderer.py
│   ├── models/             # Data models
│   │   └── data_model.py   # Project, Component, Sketch, Body
│   └── main.py             # Application entry point
├── tests/
│   └── test_geometry.py
└── pyproject.toml
```

## Installation

```bash
# Create virtual environment
python -m venv .venv
source .venv/bin/activate  # On Windows: .venv\Scripts\activate

# Install dependencies
pip install -e ".[dev]"
```

## Dependencies

| Package | Purpose |
|---------|---------|
| cadquery | High-level OpenCASCADE Python bindings |
| ocp | Low-level OpenCASCADE Python bindings |
| pygfx | WebGPU-based 3D renderer |
| wgpu | WebGPU Python bindings |
| PySide6 | Qt GUI framework |
| numpy | Numerical computing |
| scipy | Scientific computing |

## Usage

```bash
# Run the application
fluency-cad

# Or directly
python -m fluency.main
```

## API Example

```python
from fluency.geometry_occ.kernel import OCGeometryKernel
from fluency.geometry.base import Point2D

# Create kernel
kernel = OCGeometryKernel()

# Create a sketch
points = [
    Point2D(0, 0),
    Point2D(10, 0),
    Point2D(10, 10),
    Point2D(0, 10),
]
polygon = kernel.create_polygon(points)

# Extrude to 3D
body = kernel.extrude(polygon, height=20.0)

# Apply fillet
body = kernel.fillet(body, radius=2.0)

# Export to STEP
kernel.export_step(body, "part.step")

# Export to STL
kernel.export_stl(body, "part.stl")
```

## Comparison: Before vs After

| Aspect | Before (SDF + VTK) | After (OCC + pygfx) |
|--------|-------------------|---------------------|
| Geometry Precision | Approximate (mesh) | Exact (BRep) |
| Export Formats | STL only | STEP, IGES, STL, BREP |
| File Size | Large (mesh) | Small (BRep) |
| Fillet/Chamfer | Approximate | Exact |
| Dependency Size | ~200MB (VTK) | ~30MB (pygfx) |
| Constraint Solver | SolveSpace (separate) | CadQuery (integrated) |

## License

MIT License