I ran into such a problem, when working on a rig -
There is simple IK setup for a foot. 2 joints have both IK tags and Constrain tags for upVectors. IK tag goes first and then goes Contastrain tag. Everything works fine.
When I try to export the scene to fbx format, after the export the tags switch places. So now Constrain tag is first and IK - second. And in this setup upVector doesn't work.
So it doesn't work correctly, when baked into fbx. Does anyone know why this happens and any way to avoid it?
Another variant I was thinking about is replacing the upVector constrain with xPresso, but can't get my head aroung it yet.
Any help would be greatly appreciated.
Scene file attached.