sdf.primitives.LoftedPolygon

sdf.primitives.LoftedPolygon(vertices_a, vertices_b, height, material=None)

Solid lofted between two polygon profiles along the local Z axis.

Profile A lies at z = -height/2, profile B at z = +height/2; each slice in between is the per-vertex linear interpolation of the two vertex loops. Use Translate/Rotate — or the construction-layer :func:cadjoint.construction.loft — for placement.

Vertex parameter references are preserved for both profiles, so sketch constraints and gradients keep acting on the generated solid.

Parameters

Name	Type	Description	Default
vertices_a	list[Vector2]	Ordered profile-A vertices — Vector2 parameters (or raw (2,) arrays).	required
vertices_b	list[Vector2]	Ordered profile-B vertices; must match vertices_a in count, with vertex i connecting to vertex i.	required
height	float | Scalar	Total loft height (Scalar parameter or float).	required
material		Optional render material.	None

Methods

Name	Description
patch_fields	Wall planes plus the two caps — but only when every wall is flat.
sdf	Pure SDF: per-slice exact polygon distance to the lerped profile.

patch_fields

sdf.primitives.LoftedPolygon.patch_fields()

Wall planes plus the two caps — but only when every wall is flat.

Order matches :class:~cadjoint.sdf.primitives.polygon.ExtrudedPolygon: patch k (for k < N) is the wall between profile edge (v_k, v_{k+1}) and its partner (w_k, w_{k+1}); patch N is the bottom cap (z = -height/2), patch N+1 the top.

A loft wall is in general a ruled surface — the straight line joining the two edges sweeps as it goes, and sweeps out of plane the moment the two edges are not parallel — and a ruled surface is none of the plane, cylinder, sphere or cone a consumer can certify. It is a plane exactly when the wall’s four corners are coplanar, which is the common case in practice because it covers every truncated pyramid: two scaled copies of one profile, which is what a flared port or a draughted pad is. So :func:_planar_walls measures every wall, and the node declares all-or-nothing: one ruled wall and the whole node returns None, because a partial decomposition would silently hide that wall’s surface rather than fall back to one opaque patch.

What is declared for a flat wall is the plane through its four corners, outward-oriented and unit-gradient. That is the analytic continuation of what :meth:sdf computes there rather than a copy of it: the sdf measures within the horizontal slice, which is the same zero set scaled by 1/|n_xy| — a wall tilted 60° off vertical would read twice the true distance and win ownership it should lose. Two further differences, both outside the surface and so both harmless: the sdf clamps its interpolation parameter past the caps, where this plane simply keeps going; and the sdf is a bound rather than an exact distance away from the wall, while a plane’s field is exact everywhere.

Returns

Name	Type	Description
		N + 2 fields, or None when any wall is ruled.

sdf

sdf.primitives.LoftedPolygon.sdf(p, height, **vertices)

Pure SDF: per-slice exact polygon distance to the lerped profile.

Parameters

Name	Type	Description	Default
p	Array	Query point(s), shape (…, 3). Profile plane is local XY.	required
height	Array	Total loft height; the solid spans ±height/2 in Z.	required
**vertices	Array	v0..v{N-1} profile-A and w0..w{N-1} profile-B vertices, each shape (2,).	{}

Returns

Name	Type	Description
	Array	Signed distance bound, shape (…). Sign-correct while every
	Array	interpolated slice polygon is simple.