Quantization creates invalid skinning weights for CesiumMan.glb

donmccurdy / glTF-Transform

glTF 2.0 SDK for JavaScript and TypeScript, on Web and Node.js.

https://gltf-transform.dev

MIT License

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Quantization creates invalid skinning weights for CesiumMan.glb #1404

Closed donmccurdy closed 4 months ago

donmccurdy commented 6 months ago

Quantizing CesiumMan with gltf-transform quantize CesiumMan.glb CesiumMan+quant.glb we see validation errors and visible 'spikes' in the geometry. Problem appears related to sorting and normalizing the skinning weights. Tested in v4-alpha.

CesiumMan.glb.zip

https://github.com/donmccurdy/glTF-Transform/blob/13fbccffa50f9d0ab0f9b68413817a9cd6f37191/packages/functions/src/sort-primitive-weights.ts#L74-L75

https://discourse.threejs.org/t/gltf-meshopt-compression/66244/2

marwie commented 4 months ago

Just saw this issue appear in one of our meshes here as well - draco doesn't have this issue but in this case meshopt is much preferred due to blendshape compression 😊

donmccurdy commented 4 months ago

In progress:

https://github.com/donmccurdy/glTF-Transform/pull/1439

marwie commented 4 months ago

Thanks a lot for the superfast fix!