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 SolveSpace
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

# 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-ocp	OpenCASCADE Python bindings (OCP)
pygfx	WebGPU-based 3D renderer
wgpu	WebGPU Python bindings
PySide6	Qt GUI framework
numpy	Numerical computing
scipy	Scientific computing

Usage

# Run the application
fluency-cad

# Or directly
python -m fluency.main

API Example

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)	SolveSpace (integrated)

License

MIT License