How to convert Vrm coordinates to MMD coordinates

Questions
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1

Hello, everyone. I have a question about the Vrm and MMD models. I am trying to convert programmatically obtained vrm coordinates to mmd coordinates, but it is not working well and is inaccurate. There is little information on the Internet about conversion or conversion coefficients. Who can explain in detail how to convert from one coordinate system to another?

I’m using the mediapipe holistic libraries with kalidokit, getting a yes for the vrm model and trying to convert it to mmd rotation
Source code: To method

2

I’ve never heard about these models. Is it something proprietary?

LLM tells me this:

VRM and MMD models are both 3D character model formats commonly used in anime-style rendering

for points and vectors, flip the Z components.
For quaternions, as it’s a symetry, flip x and y components.

3

I don’t know much about this, but I know VRM is a format based on glTF with some custom extensions. I don’t know MMD at all. We will need to understand both formats to answer this question.

4

unfortunately, this doesn’t work, I’m closer to the ideal option in my code, but it’s 50% perfect.