I had tried using the parentRelativeAttachment before, and would love to use it, but the issue for me is that I need to drive the base body movement from the pelvis and not the head. Otherwise my IK looks funky because when I rotate my head the whole underlying animation is rotated.
I tried adding an extra parentRelativeAttachment component besides the inherited one, and attaching it beneath my pelvis tracker in hopes that it would use that as the parent, but it still seems tied to the HMD as the parent. Is there any way to make it accept any parent rather than just HMD? I think if I could have the pelvis tracker as parent it would work well for my body tracking setup.