Solid features

Extrude and revolve

const profile = cad.sketch("profile", plane.xy(), (sketch) =>
  sketch.profile(
    sketch.rectangle("outline", {
      width: mm(40),
      height: mm(20),
      center: vec2(mm(30), mm(0)),
    }),
  ),
);

const extrusion = cad.extrude("extrusion", profile, {
  distance: mm(10),
  symmetric: true,
});

const revolution = cad.revolve("revolution", profile, {
  angle: deg(270),
  segments: 96,
});

Revolve turns the profile about the sketch plane’s local v axis through the sketch origin, the line u = 0 in sketch coordinates. For plane.xy() that is the world Y axis. The whole profile must lie on one side of the axis; it may touch the axis (a profile starting at u = 0 gives a solid with no bore), but it cannot cross it. Here the rectangle spans u = 10..50. A profile with material on both sides fails with FEATURE_INVALID at /nodes/<id>/profile (reason profile-crosses-axis) before any kernel call, so Manifold and OCCT reject it the same way. segments is a Manifold tessellation hint; OCCT revolves exactly and ignores it. Manifold additionally supports twisted and top-scaled extrusion:

const twisted = cad.extrude("twisted", profile, {
  distance: mm(50),
  twist: deg(90),
  scaleTop: [scalar(0.75), scalar(0.75)],
  divisions: 32,
});

Check the support matrix before using these options with another kernel.

Booleans

Boolean features have one target and one or more tools:

const joined = cad.union("joined", target, [toolA, toolB]);
const cut = cad.subtract("cut", target, [holeA, holeB]);
const common = cad.intersect("common", target, [clip]);

An empty tool array is rejected during authoring. The result is one solid; input solids remain feature dependencies and are not mutated.

Exact-kernel features

Fillet, chamfer, shell, and whole-solid offset are exact B-Rep features. The default Manifold kernel from createEvaluator() advertises only extrude, revolve, Boolean, and transform, so these examples fail there with KERNEL_CAPABILITY_MISSING. Evaluate them with stock OCCT:

const evaluator = await createEvaluator({ profile: "mechanical-exact" });

See the support matrix for each kernel’s feature and topology-history coverage.

Fillet and chamfer

Edge treatments require an explicit edge selection:

const rim = topology.edges
  .createdBy(extrusion, { role: "extrude.edge.end-rim" })
  .exactly(4);

const rounded = cad.fillet("rounded", extrusion, {
  edges: rim,
  radius: mm(2),
});

const beveled = cad.chamfer("beveled", extrusion, {
  edges: rim,
  distance: mm(1),
});

The selection resolves against the direct input solid. A missing, ambiguous, or wrong-cardinality selection fails before the treatment is applied. Selected edges are seeds, not hard boundaries. After the cardinality check, each seed expands to its maximal connected tangent contour: consecutive edges must meet tangentially, and the faces on both sides of the contour must also continue tangentially. One selected edge can therefore round or bevel a whole tangent chain. Cardinality counts the seeds, not the edges finally treated, and seeds on the same contour apply the treatment once.

Shell and offset

const endCap = topology.faces
  .createdBy(extrusion, { role: "extrude.face.end-cap" })
  .select();

const hollow = cad.shell("hollow", extrusion, {
  openings: endCap,
  thickness: mm(2),
  direction: "inward",
  tolerance: mm(1e-6),
});

const expanded = cad.offset("expanded", extrusion, {
  distance: mm(1),
  direction: "outward",
  tolerance: mm(1e-6),
});

Shell removes selected opening faces and offsets the remaining skin to create a constant wall. Whole-solid offset has no opening selection. Both use positive magnitudes plus an explicit direction.

Draft

Draft is an atomic multi-face exact feature available through the matched owned OCCT facade:

const sides = topology.faces
  .createdBy(extrusion, { role: "extrude.face.side" })
  .atLeast(1);

const drafted = cad.draft("drafted", extrusion, {
  faces: sides,
  angle: deg(2),
  pullDirection: scalarVec3(0, 0, 1),
  neutralPlane: {
    origin: vec3(mm(0), mm(0), mm(0)),
    normal: scalarVec3(0, 0, 1),
  },
});

Stock OCCT does not advertise draft. Capability checks reject the feature before input geometry is allocated on an unsupported backend.

Exact-history boundary

Stock OCCT can construct most exact features, but its Boolean, edge-treatment, and solid-offset topology history is partial. The optional owned facade advertises complete bounded evolution only for the exact feature slices and ABI versions documented in the OpenCascade guide. Construction success and complete topology evolution are distinct guarantees.

Getting started

Modeling

Evaluation

Analysis and interchange