Three.js: GLTF2Loader -- support for CUBICSPLINE interpolation

[zellski]

I've noticed that GLTF2Loader is undergoing fairly rapid iteration. Is there work in progress on supporting the new interpolation modes, most interestingly CUBICSPLINE? Of all the improvements from GLTF1 to GLTF2, getting away from densely sampled animation transforms (and the resulting enormous model files) is perhaps the most exciting.

If nobody else is working on this, we may end up taking a pass on it.

[donmccurdy]

Is there work in progress on supporting the new interpolation modes, most interestingly CUBICSPLINE?

Not started yet, no. Please do feel free to work on this. 🙂

/cc @takahirox

[donmccurdy]

Regarding the ongoing iteration, my own roadmap currently is:

1. Supporting experimental Draco mesh compression extension for glTF
2. KHR_cmnBlinnPhong extension
3. Refactoring to allow glTF extensions to be authored without modifying GLTF2Loader itself.

[donmccurdy]

CUBICSPLINE interpolation added with https://github.com/mrdoob/three.js/pull/11825. If you have a test model available, might be good to verify.

[zellski]

Great work! I believe the Blender folks are adding support for spline interpolation in their exporter shortly. Meanwhile I might hack up a tiny test-file by hand.

[donmccurdy]

Unfortunately it looks like CUBICSPLINE interpolation will need some more work. I tried passing the glTF data directly into the three.js keyframe track and that wasn't it. Will need to read up on how both systems work and adapt the input data accordingly. See: #12233.

[zellski]

Aha, understood. You need a little McCurdy-minion to help you out.