freecad-scripts

# 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(10) # radius cone = Part.makeCone(5, 2, 10) # r1, r2, height torus = Part.makeTorus(10, 2) # major_r, minor_r # --- Wires and Edges --- edge1 = Part.makeLine((0, 0, 0), (10, 0, 0)) edge2 = Part.makeLine((10, 0, 0), (10, 10, 0)) edge3 = Part.makeLine((10, 10, 0), (0, 0, 0)) wire = Part.Wire([edge1, edge2, edge3]) # Circles and arcs circle = Part.makeCircle(5) # radius arc = Part.makeCircle(5, FreeCAD.Vector(0, 0, 0), FreeCAD.Vector(0, 0, 1), 0, 180) # start/end angle # --- Faces --- face = Part.Face(wire) # From a closed wire # --- Solids from Faces/Wires --- extrusion = face.extrude(FreeCAD.Vector(0, 0, 10)) # Extrude revolved = face.revolve(FreeCAD.Vector(0, 0, 0), FreeCAD.Vector(0, 0, 1), 360) # Revolve # --- Boolean Operations --- fused = box.fuse(cyl) # Union cut = box.cut(cyl) # Subtraction common = box.common(cyl) # Intersection fused_clean = fused.removeSplitter() # Clean up seams # --- Fillets and Chamfers --- filleted = box.makeFillet(1.0, box.Edges) # radius, edges chamfered = box.makeChamfer(1.0, box.Edges) # dist, edges # --- Loft and Sweep --- loft = Part.makeLoft([wire1, wire2], True) # wires, solid swept = Part.Wire([path_edge]).makePipeShell([profile_wire], True, False) # solid, frenet # --- BSpline Curves --- from FreeCAD import Vector points = [Vector(0,0,0), Vector(1,2,0), Vector(3,1,0), Vector(4,3,0)] bspline = Part.BSplineCurve() bspline.interpolate(points) edge = bspline.toShape() # --- Show in document --- Part.show(box, "MyBox") # Quick display (adds to active doc) # Or explicitly: doc = FreeCAD.ActiveDocument or FreeCAD.newDocument() obj = doc.addObject("Part::Feature", "MyShape") obj.Shape = box doc.recompute() ``` ### Topological Exploration ```python shape = obj.Shape # Access sub-elements shape.Vertexes # List of Vertex objects shape.Edges # List of Edge objects shape.Wires # List of Wire objects shape.Faces # List of Face objects shape.Shells # List of Shell objects shape.Solids # List of Solid objects # Bounding box bb = shape.BoundBox print(bb.XMin, bb.XMax, bb.YMin, bb.YMax, bb.ZMin, bb.ZMax) print(bb.Center) # Properties shape.Volume shape.Area shape.Length # For edges/wires face.Surface # Underlying geometric surface edge.Curve # Underlying geometric curve # Shape type shape.ShapeType # "Solid", "Shell", "Face", "Wire", "Edge", "Vertex", "Compound" ``` ### Mesh Module ```python import Mesh # Create mesh from vertices and facets mesh = Mesh.Mesh() mesh.addFacet( 0.0, 0.0, 0.0, # vertex 1 1.0, 0.0, 0.0, # vertex 2 0.0, 1.0, 0.0 # vertex 3 ) # Import/Export mesh = Mesh.Mesh("/path/to/file.stl") mesh.write("/path/to/output.stl") # Convert Part shape to Mesh import Part import MeshPart shape = Part.makeBox(1, 1, 1) mesh = MeshPart.meshFromShape(Shape=shape, LinearDeflection=0.1, AngularDeflection=0.5) # Convert Mesh to Part shape shape = Part.Shape() shape.makeShapeFromMesh(mesh.Topology, 0.05) # tolerance solid = Part.makeSolid(shape) ``` ### Sketcher Module # Create a sketch on XY plane sketch = doc.addObject("Sketcher::SketchObject", "MySketch") sketch.Placement = FreeCAD.Placement( FreeCAD.Vector(0, 0, 0), FreeCAD.Rotation(0, 0, 0, 1) ) # Add geometry (returns geometry index) idx_line = sketch.addGeometry(Part.LineSegment( FreeCAD.Vector(0, 0, 0), FreeCAD.Vector(10, 0, 0))) idx_circle = sketch.addGeometry(Part.Circle( FreeCAD.Vector(5, 5, 0), FreeCAD.Vector(0, 0, 1), 3)) # Add constraints sketch.addConstraint(Sketcher.Constraint("Coincident", 0, 2, 1, 1)) sketch.addConstraint(Sketcher.Constraint("Horizontal", 0)) sketch.addConstraint(Sketcher.Constraint("DistanceX", 0, 1, 0, 2, 10.0)) sketch.addConstraint(Sketcher.Constraint("Radius", 1, 3.0)) sketch.addConstraint(Sketcher.Constraint("Fixed", 0, 1)) # Constraint types: Coincident, Horizontal, Vertical, Parallel, Perpendicular, # Tangent, Equal, Symmetric, Distance, DistanceX, DistanceY, Radius, Angle, # Fixed (Block), InternalAlignment doc.recompute() ``` ### Draft Module ```python import Draft import FreeCAD # 2D shapes line = Draft.makeLine(FreeCAD.Vector(0,0,0), FreeCAD.Vector(10,0,0)) circle = Draft.makeCircle(5) rect = Draft.makeRectangle(10, 5) poly = Draft.makePolygon(6, radius=5) # hexagon # Operations moved = Draft.move(obj, FreeCAD.Vector(10, 0, 0), copy=True) rotated = Draft.rotate(obj, 45, FreeCAD.Vector(0,0,0), axis=FreeCAD.Vector(0,0,1), copy=True) scaled = Draft.scale(obj, FreeCAD.Vector(2,2,2), center=FreeCAD.Vector(0,0,0), copy=True) offset = Draft.offset(obj, FreeCAD.Vector(1,0,0)) array = Draft.makeArray(obj, FreeCAD.Vector(15,0,0), FreeCAD.Vector(0,15,0), 3, 3) ``` ## Creating Parametric Objects (FeaturePython) FeaturePython objects are custom parametric objects with properties that trigger recomputation: ```python import FreeCAD import Part class MyBox: """A custom parametric box.""" def __init__(self, obj): obj.Proxy = self obj.addProperty("App::PropertyLength", "Length", "Dimensions", "Box length").Length = 10.0 obj.addProperty("App::PropertyLength", "Width", "Dimensions", "Box width").Width = 10.0 obj.addProperty("App::PropertyLength", "Height", "Dimensions", "Box height").Height = 10.0 def execute(self, obj): """Called on document recompute.""" obj.Shape = Part.makeBox(obj.Length, obj.Width, obj.Height) def onChanged(self, obj, prop): """Called when a property changes.""" pass def __getstate__(self): return None def __setstate__(self, state): return None class ViewProviderMyBox: """View provider for custom icon and display settings.""" def __init__(self, vobj): vobj.Proxy = self def getIcon(self): return ":/icons/Part_Box.svg" def attach(self, vobj): self.Object = vobj.Object def updateData(self, obj, prop): pass def onChanged(self, vobj, prop): pass def __getstate__(self): return None def __setstate__(self, state): return None # --- Usage --- doc = FreeCAD.ActiveDocument or FreeCAD.newDocument("Test") obj = doc.addObject("Part::FeaturePython", "CustomBox") MyBox(obj) ViewProviderMyBox(obj.ViewObject) doc.recompute() ``` ### Common Property Types | Property Type | Python Type | Description | |---|---|---| | `App::PropertyBool` | `bool` | Boolean | | `App::PropertyInteger` | `int` | Integer | | `App::PropertyFloat` | `float` | Float | | `App::PropertyString` | `str` | String | | `App::PropertyLength` | `float` (units) | Length with units | | `App::PropertyAngle` | `float` (deg) | Angle in degrees | | `App::PropertyVector` | `FreeCAD.Vector` | 3D vector | | `App::PropertyPlacement` | `FreeCAD.Placement` | Position + rotation | | `App::PropertyLink` | object ref | Link to another object | | `App::PropertyLinkList` | list of refs | Links to multiple objects | | `App::PropertyEnumeration` | `list`/`str` | Dropdown selection | | `App::PropertyFile` | `str` | File path | | `App::PropertyColor` | `tuple` | RGB color (0.0-1.0) | | `App::PropertyPythonObject` | any | Serializable Python object | ## Creating GUI Tools ### Gui Commands ```python import FreeCAD import FreeCADGui class MyCommand: """A custom toolbar/menu command.""" def GetResources(self): return { "Pixmap": ":/icons/Part_Box.svg", "MenuText": "My Custom Command", "ToolTip": "Creates a custom box", "Accel": "Ctrl+Shift+B" } def IsActive(self): return FreeCAD.ActiveDocument is not None def Activated(self): # Command logic here FreeCAD.Console.PrintMessage("Command activated\n") FreeCADGui.addCommand("My_CustomCommand", MyCommand()) ``` ### PySide Dialogs ```python from PySide2 import QtWidgets, QtCore, QtGui class MyDialog(QtWidgets.QDialog): def __init__(self, parent=None): super().__init__(parent or FreeCADGui.getMainWindow()) self.setWindowTitle("My Tool") self.setMinimumWidth(300) layout = QtWidgets.QVBoxLayout(self)