Bug report / バグ報告: Missing humanoid hips in some re-exported VRM files

[evshiron]

Describe the bug / バグについて I am playing with this avatar, and have encountered strange pose in VRM Viewer.

Other avatars like this don't have this issue.

I try importing and exporting in Unity with UniVRM, and the exported VRM file doesn't have this issue neither.

I am new to VRM and can't figure out what's wrong with the steps, so I assume it to be a bug.

To Reproduce / バグの再現方法 Steps to reproduce the behavior:

1. Launch Blender, delete the default cube, and import this VRM file (a.vrm)
2. Export as another VRM file (b.vrm)
3. Open VRM Viewer and load b.vrm, and select Pose > ダブルピース
4. See error The console show that Humaniod Hips can not be found.

Expected behavior / 期待する動作 When you repeat step 3 with a.vrm, the expected result is shown above.

Screenshots / スクリーンショット If applicable, add screenshots to help explain your problem. 何か参考になりそうなスクショがあれば添付してください。

Desktop (please complete the following information) / PC環境情報

• OS: Windows 10
• Blender 3.0.0
• Addon Version 2.3.6

Additional context / なにか他に書いておきたいことはこちらへ Add any other context about the problem here.

[saturday06]

It is most likely a bug in VRM Viewer. I followed your steps and the Humanoid Hips were exported correctly.

[evshiron]

Yep, but when I edited and exported in Unity, the file worked properly in VRM Viewer. There might be some differences I guess.

I am writing a script to diagnosis a bit and will report back later.

[saturday06]

I think https://github.com/pixiv/three-vrm/pull/577/files is probably related.

[evshiron]

Nice catch! I find that VRM Viewer is using a very old version of @pixiv/three-vrm, and when I update to the latest version (which is 0.6.10), the issue is gone.