JSCAD geometry engine project

[platypii]

Hey everyone. I was just added as a maintainer of JSCAD

I've recently been getting a bunch of commits in (with the help of @z3dev, @hrgdavor, and others) trying to make the geometry internals of JSCAD both rock solid, and super fast.

Some recent improvements:

• 100x speedup of toOutlines for large polys
• 150x speedup of hullPath2 for large polys
• 2.6x speedup of expandShell for 3D expansions. Also produces cleaner output geometry.
• 300x speedup of offsetFromPoints for 2D expansions. Also cleaner output geometry.

Some bigger projects I'm working on:

• Earcut triangulation. Currently extrusions use toPolygons to turn non-convex geometries into convex polygons. But there are known bugs (#907). I believe this can be done faster, and produce air-tight geometry!
• Fixes to offsetFromPoints. A user reported a bug in our offset code (#1017). Polygon offsetting is a hard problem in computational geometry. I think we can fix the user bug, but getting a fully general solution may not be easy.
• Eliminate non-manifold geometry from the output of BSP trees. Still early in experiments, but I think it's possible to efficiently produce manifold geometry. This would be more robust to floating point errors (quantization would not break edges). And allow non-linear transforms (for example, bending an object #598).

I really like the JSCAD API. V2 was a beautiful upgrade. I want to make the engine implementing that API as fast and accurate as humanly possible.

[z3dev]

For those wondering, @platypii is a new member of the development team. He’s already put together some super nice fixes. In addition, he never sleeps so things are moving along at light speed.

So, please let him know if there’s something missing from JSCAD.