https://www.posetteforever.com/viewtopic.php?f=1&t=4072&p=45743#p45743
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ahjah
Tuesday, 05 April 2022, 05:45 PM

Re: External Morph Targets Unstable Beyond 90 Deg ??
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That's an issue with how obj based morphs work in Poser. It's the same with rotations created by magnets an then saved as an (obj)morph. The obj only saves the end position, in this case 90°. If you move the dial, the vertices are simply shifted linear from the zero position to end position. Thats why the lid is shorter inbetween this two positions. If you go beyond endposition the linear shifting continues and the lid explodes. This is why there's a thing like rigged cr2 for real rotation.
I never worked with MMD PMX, but I assume what they call a morph isn't the same as a Poser obj based morph, but actually rig information as in a cr2, i.e. pivot point and bone to rotate. Seems like this information gets lost in your workflow.
First workaround would be (for me) to import box and lid as separate obj and parent the lid to the the box (with the pivot set where it should be) Also you could make a simple cr2 from it. Import the obj as a whole and group it into "box" and "lid" and then setup the lid bone with a rotation center