KhronosGroup / KhronosGroup/COLLADA2GLTF

Something wrong with mesh bindings to bones after conversion from Collada

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#13 8 comments 0 reactions 0 assignees View on GitHub
bug legacy
Dominant language
C++
Stars
573
Forks
154
PR merge metrics
No merged PRs in 30d

Description

I have a 3D model exported from Blender to Collada. It looks well and as expected in any collada preview application, but with problems after conversion to GLTF in Three.js. The follow link contains an archive with the .dae file and movies which show how it looks in collada preview and in browser rendered by Three.js.
[gltf_bug_report.zip](https://github.com/KhronosGroup/COLLADA2GLTF/files/693976/gltf_bug_report.zip)
The blue shell around the person is ice which should moves only in freezing sequence of the animation, but it somehow moves with another bones which weren't binded to that mesh and not moves in the freezing sequence (you can see freezing effect at 0:06 in shooter_gltf_bug.mov), but bones of the shell are moves correctly (I added green dots which represent the real position of the bones). You can compare it with how it should work in .dae file.
Therefore it looks like the bindings mesh vertices to bones somehow worked erroneously during conversion process.

Contributor guide

No contributing guide indexed for this repository

Research direction

Start by reproducing the conversion with the attached gltf_bug_report.zip, comparing the .dae preview with the converted GLTF rendered in Three.js. Inspect the mesh-to-bone bindings involved in the ice shell and freezing animation; done means the shell moves only with its intended bones and matches the COLLADA behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp, three.js
Domain
computer-graphics
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
35/100

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