Cameron White

To add resistant to rotation (while still within the limits), you can turn on Enable Motor and Target Current Pose, which will try to maintain the current relative orientation depending on the motor's strength

Would you be able to attach your file (or submit it to SideFX support)?
It sounds like there is definitely something going wrong, especially if both importing as UsdSkel and importing as a mesh are not working well..

If a USD curves prim has no `widths` attribute authored, I think Hydra will default to displaying it with a width of 1.0
This is coming from the `main_ctrl_nurbs_curve0` shape which you probably don't want to render anyways - you could either filter that out as you're importing the agent from FBX (using the KineFX route of FBX Character Import -> Agent from Rig -> Agent Layer etc gives you the most flexibility to remove and alter shapes), or use the Agent Layer SOP to just create a new layer which contains the skin geometry but not that curve shape