CadCraft™ v0.9.0
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Engine

NURBS surfaces

Curves and surfaces, STEP/IGES.

Screenshot from the lab build. NURBS surfaces: a lofted surface with zebra stripes for smoothness
Screenshot from the lab build. NURBS surfaces: a lofted surface with zebra stripes for smoothness

Built on it

No add-on yet. Yours could be the first.

Use it in your add-on

Name it in your manifest's needs. When someone adds your add-on, their account brings this engine too, and every edition loads it the first time your add-on needs it. Version ranges arrive with AL.13.

{
  "id": "com.example.my-addon",
  "apps": ["modelcraft", "partcraft"],
  "needs": ["engine.nurbs"]
}

Methods and standards

Curve and surface evaluation, knot insertion and removal, degree elevation and reduction, interpolation and approximation, following The NURBS Book (Piegl and Tiller); its worked examples are the known answers in the tests. Continuity is measured on the exact surfaces. The defaults in this version are G0 0.01 mm, G1 0.1 degrees and G2 0.001 per mm or 1 %, whichever is looser, with 33 samples per edge. The code was written from published sources only. Trimming, sewing into solids and n-sided patch fill are not built.

Limits

A library, not a finished tool: there are no trimmed surfaces, no solids, no fillets between trimmed faces and no n-sided patch fill, and no curve projection or curve-surface intersection. Continuity is measured to G2 only; G3 and class-A surface quality are not claimed. Trimming and solids wait on a separate decision about the exact geometry kernel. Speed figures from the shared build server are not reliable and are not quoted.