The one thing I see is that fragmotion shows a more the 65000 vertices error.
And that may be causing most of your grief.
Can you email me an OBJ or an FBX of you model, and I can see if the meshes doubled or what.
Try attaching these all together as 1 object and then perform a weld operation at 3mm and see if that reduces the vertices count, making it possible to see all of it and have proper collision.
Or
Split the model in pieces based on the stone radius and have 3 objects make up the total structure, all with the same insert point. This will ease the work the engine has to perform also. And reduce the vertices count Down per object.
I also noticed in your FPE files that in real life these are 300% smaller then what is shown in the editor. Sometime collision errors can occur like this also. Maybe have them come in the editor at 100 and then scale them up there. Or just upscale them on the export, if your exporter has that option. If not then, Scale them up in the model program instead.
But I am going to go with vertices count on this one I believe.
Let me know if my hunch is correct.
Thanks
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