OpenCASCADE Python

Python bindings for the OpenCASCADE CAD kernel.

Installation

pip install cadquery-ocp  # OCP bindings
# or
conda install -c conda-forge pythonocc-core

Basic Shapes with OCP

from OCP.BRepPrimAPI import (
    BRepPrimAPI_MakeBox,
    BRepPrimAPI_MakeCylinder,
    BRepPrimAPI_MakeSphere
)
from OCP.gp import gp_Pnt, gp_Vec, gp_Ax2, gp_Dir

# Create box
box = BRepPrimAPI_MakeBox(10, 20, 30).Shape()

# Create cylinder
cylinder = BRepPrimAPI_MakeCylinder(5, 20).Shape()

# Create sphere
sphere = BRepPrimAPI_MakeSphere(10).Shape()

Boolean Operations

from OCP.BRepAlgoAPI import (
    BRepAlgoAPI_Fuse,
    BRepAlgoAPI_Cut,
    BRepAlgoAPI_Common
)

# Union
fused = BRepAlgoAPI_Fuse(shape1, shape2).Shape()

# Subtraction
cut = BRepAlgoAPI_Cut(base, tool).Shape()

# Intersection
common = BRepAlgoAPI_Common(shape1, shape2).Shape()

Transformations

from OCP.gp import gp_Trsf, gp_Vec
from OCP.BRepBuilderAPI import BRepBuilderAPI_Transform

# Create transformation
trsf = gp_Trsf()
trsf.SetTranslation(gp_Vec(10, 0, 0))

# Apply to shape
transform = BRepBuilderAPI_Transform(shape, trsf)
moved_shape = transform.Shape()

# Rotation
trsf.SetRotation(gp_Ax1(gp_Pnt(0,0,0), gp_Dir(0,0,1)), 3.14159/4)

NURBS and Curves

from OCP.Geom import Geom_BSplineCurve
from OCP.TColgp import TColgp_Array1OfPnt
from OCP.TColStd import TColStd_Array1OfReal, TColStd_Array1OfInteger

# Define control points
points = TColgp_Array1OfPnt(1, 4)
points.SetValue(1, gp_Pnt(0, 0, 0))
points.SetValue(2, gp_Pnt(1, 2, 0))
points.SetValue(3, gp_Pnt(3, 2, 0))
points.SetValue(4, gp_Pnt(4, 0, 0))

# Create B-spline
curve = Geom_BSplineCurve(points, knots, multiplicities, degree)

File I/O

from OCP.STEPControl import STEPControl_Reader, STEPControl_Writer

# Read STEP
reader = STEPControl_Reader()
reader.ReadFile("input.step")
reader.TransferRoots()
shape = reader.OneShape()

# Write STEP
writer = STEPControl_Writer()
writer.Transfer(shape, STEPControl_AsIs)
writer.Write("output.step")

Topology Exploration

from OCP.TopExp import TopExp_Explorer
from OCP.TopAbs import TopAbs_FACE, TopAbs_EDGE

# Iterate faces
explorer = TopExp_Explorer(shape, TopAbs_FACE)
faces = []
while explorer.More():
    faces.append(explorer.Current())
    explorer.Next()