build123d

# build123d CAD Modeling

## Zero-Setup with uv

No installation required. Run any build123d script with:

```bash
uvx --from build123d python script.py
```

This automatically downloads build123d and runs your script. First run takes ~30s, subsequent runs are instant.

**Install uv** (if not already installed):
```bash
curl -LsSf https://astral.sh/uv/install.sh | sh
```

## Critical: Imports

All exports are in the **main module**:

```python
from build123d import Sphere, Box, Cylinder, export_gltf, export_step, export_stl
```

**NEVER** use `from build123d.exporters import ...` - this module does not exist.

## Quick Start Example

```python
#!/usr/bin/env python3
from build123d import Sphere, Box, export_gltf, Pos

# Create shapes
sphere = Sphere(radius=20)
box = Pos(15, 0, 0) * Box(10, 10, 10)

# Boolean union
result = sphere + box

# Export to GLB (for web viewers, Three.js)
export_gltf(result, "./model.glb", binary=True)
print("Exported model.glb")
```

Run it:
```bash
uvx --from build123d python my_model.py
```

## Geometry Inspection (Optional)

To inspect geometry properties, add this to your script:

```python
def inspect(shape):
    bbox = shape.bounding_box()
    print(f"Size: {bbox.max.X - bbox.min.X:.1f} x {bbox.max.Y - bbox.min.Y:.1f} x {bbox.max.Z - bbox.min.Z:.1f}")
    print(f"Volume: {shape.volume:.1f}")
    print(f"Faces: {len(shape.faces())}, Edges: {len(shape.edges())}")

inspect(result)
```

A full inspection harness is available in `scripts/harness.py` for advanced use.

## Quick Reference

### Shapes
```python
Box(length, width, height)
Sphere(radius=20)
Cylinder(radius=10, height=25)
Cone(bottom_radius=15, top_radius=5, height=20)
Torus(major_radius=20, minor_radius=5)
```

### Boolean Operations
```python
union = shape1 + shape2           # Fuse
difference = shape1 - shape2      # Cut
intersection = shape1 & shape2    # Common volume
```

### Positioning
```python
from build123d import Pos, Rot
moved = Pos(x, y, z) * shape      # Translate