OpenMotionLab / MotionGPT

[NeurIPS 2023] MotionGPT: Human Motion as a Foreign Language, a unified motion-language generation model using LLMs
https://motion-gpt.github.io
MIT License
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Coordinate space in which joint rotations were calculated with HybrIKJointsToRotmat #70

Open UnrealXinda opened 8 months ago

UnrealXinda commented 8 months ago

Hi, first off, thanks for the awesome work. I have a question regarding the coordinate space in which the rotation matrices were calculated. The joint positions inferred by the model is clearly in world space (which I can confirm by sketching them out). However, with regard to the joint rotations that were calculated using the HybrIKJointsToRotmat model, I'm not entirely sure which coordinate space they were in. I tried sketching them out in both component/world/local spaces and none of them seemed to fit. In particular, none of the three axes lined up with the joint connections. I'm wondering if anyone could provide some insights into this issue.