Creation and import

All Model construction methods return a new session-owned Shape. Inputs are ordinary Python numbers and sequences; coordinates are three-dimensional unless a sketch API explicitly uses 2D values.

Primitives

Method	Parameters	Result and constraints
box(width, depth, height)	positive lengths	Solid based at the model origin and extending along positive axes
cylinder(radius, height)	positive radius and height	Solid aligned with positive Z
sphere(radius)	positive radius	Closed solid centered at the model origin
cone(radius1, radius2, height)	non-negative radii, positive height	Cone or frustum aligned with positive Z; both radii cannot define a degenerate solid

with cad.Model() as model:
    plate = model.box(80.0, 50.0, 4.0)
    boss = model.cylinder(8.0, 12.0)
    body = model.union(plate, model.translate(boss, 40.0, 25.0, 4.0))

Polylines and profiles

polyline(points, closed=False) joins ordered points with straight segments. At least two distinct points are required for an open wire; a face requires a non-self-intersecting closed wire.

circle_profile(radius, center=(0, 0, 0), normal=(0, 0, 1)) returns a circular wire. The normal must be non-zero. arc(start, middle, end) constructs the arc passing through three non-collinear points.

interpolate(points, periodic=False, tolerance=1e-6) fits a curve through ordered points. periodic=True requests a closed periodic curve. helix(pitch, height, radius, center, direction) creates a helical curve along direction.

Exact B-splines

curve = model.bspline(
    control_points=((0, 0, 0), (15, 5, 0), (30, 0, 0)),
    degree=2,
    knots=(0.0, 1.0),
    multiplicities=(3, 3),
    weights=None,
    periodic=False,
)

Control-point count, degree, knot values, multiplicities, and optional weights must form a valid B-spline definition. Use interpolate when interpolation is the intent and exact knot control is unnecessary.

Faces and surfaces

Method	Input	Output
face(wire)	closed planar wire	planar face
bezier_surface(points, weights=None)	rectangular control grid	Bezier surface
fit_surface(points, tolerance=1e-3, degree_min=3, degree_max=8)	rectangular sample grid	fitted B-spline surface
ruled_surface(edge_a, edge_b)	two compatible edges	ruled face between edges
filling_surface(edges, tolerance=1e-6)	ordered boundary edges	filled face
gordon_surface(profiles, guides, tolerance=1e-6)	intersecting profile/guide networks	network surface

Surface control and sample grids must be rectangular and finite. Network surfaces require mutually compatible curve families; native construction may reject disconnected or poorly conditioned boundaries.

Import

Method	Format	Notes
import_step(path)	STEP	Exact CAD exchange geometry and assemblies reduced to a shape result
import_brep(path)	OpenCascade BREP	Native topology and geometry
import_stl(path)	STL	Tessellated input; no exact analytic surface recovery is implied

Import methods read from disk and raise an I/O or native error for missing, unreadable, malformed, or unsupported files. Query kind, bbox, topology, and validate() before using imported geometry downstream.

Exact signatures: Model and the modeling catalog.