freecad-scripts

The saved excerpt is a snapshot from when this skill was listed. The external source remains the complete and most current version.

---
name: freecad-scripts
description: 'Expert skill for writing FreeCAD Python scripts, macros, and automation. Use when asked to create FreeCAD models, parametric objects, Part/Mesh/Sketcher scripts, workbench tools, GUI dialogs with PySide, Coin3D scenegraph manipulation, or any FreeCAD Python API task. Covers FreeCAD scripting basics, geometry creation, FeaturePython objects, interface tools, and macro development.'
---

# FreeCAD Scripts

Expert skill for generating production-quality Python scripts for the FreeCAD CAD application. Interprets shorthand, quasi-code, and natural language descriptions of 3D modeling tasks and translates them into correct FreeCAD Python API calls.

## When to Use This Skill

- Writing Python scripts for FreeCAD's built-in console or macro system
- Creating or manipulating 3D geometry (Part, Mesh, Sketcher, Path, FEM)
- Building parametric FeaturePython objects with custom properties
- Developing GUI tools using PySide/Qt within FreeCAD
- Manipulating the Coin3D scenegraph via Pivy
- Creating custom workbenches or Gui Commands
- Automating repetitive CAD operations with macros
- Converting between mesh and solid representations
- Scripting FEM analyses, raytracing, or drawing exports

## Prerequisites

- FreeCAD installed (0.19+ recommended; 0.21+/1.0+ for latest API)
- Python 3.x (bundled with FreeCAD)
- For GUI work: PySide2 (bundled with FreeCAD)
- For scenegraph: Pivy (bundled with FreeCAD)

## FreeCAD Python Environment

FreeCAD embeds a Python interpreter. Scripts run in an environment where these key modules are available:

```python
import FreeCAD          # Core module (also aliased as 'App')
import FreeCADGui       # GUI module (also aliased as 'Gui') — only in GUI mode
import Part             # Part workbench — BRep/OpenCASCADE shapes
import Mesh             # Mesh workbench — triangulated meshes
import Sketcher         # Sketcher workbench — 2D constrained sketches
import Draft            # Draft workbench — 2D drawing tools
import Arch             # Arch/BIM workbench
import Path             # Path/CAM workbench
import FEM              # FEM workbench
import TechDraw         # TechDraw workbench (replaces Drawing)
import BOPTools         # Boolean operations
import CompoundTools    # Compound shape utilities
```

### The FreeCAD Document Model

```python
# Create or access a document
doc = FreeCAD.newDocument("MyDoc")
doc = FreeCAD.ActiveDocument

# Add objects
box = doc.addObject("Part::Box", "MyBox")
box.Length = 10.0
box.Width = 10.0
box.Height = 10.0

# Recompute
doc.recompute()

# Access objects
obj = doc.getObject("MyBox")
obj = doc.MyBox  # Attribute access also works

# Remove objects
doc.removeObject("MyBox")
```

## Core Concepts

### Vectors and Placements

```python
import FreeCAD

# Vectors
v1 = FreeCAD.Vector(1, 0, 0)
v2 = FreeCAD.Vector(0, 1, 0)
v3 = v1.cross(v2)          # Cross product
d = v1.dot(v2)              # Dot product
v4 = v1 + v2                # Addition
length = v1.Length           # Magnitude
v_norm = FreeCAD.Vector(v1)
v_norm.normalize()           # In-place normalize

# Rotations
rot = FreeCAD.Rotation(FreeCAD.Vector(0, 0, 1), 45)  # axis, angle(deg)
rot = FreeCAD.Rotation(0, 0, 45)                       # Euler angles (yaw, pitch, roll)

# Placements (position + orientation)
placement = FreeCAD.Placement(
    FreeCAD.Vector(10, 20, 0),    # translation
    FreeCAD.Rotation(0, 0, 45),   # rotation
    FreeCAD.Vector(0, 0, 0)       # center of rotation
)
obj.Placement = placement

# Matrix (4x4 transformation)
import math
mat = FreeCAD.Matrix()
mat.move(FreeCAD.Vector(10, 0, 0))
mat.rotateZ(math.radians(45))
```

### Creating and Manipulating Geometry (Part Module)

The Part module wraps OpenCASCADE and provides BRep solid modeling:

```python
import FreeCAD
import Part

# --- Primitive Shapes ---
box = Part.makeBox(10, 10, 10)               # length, width, height
cyl = Part.makeCylinder(5, 20)               # radius, height
sphere = Part.makeSphere