I started looking into physics-based animation, but I am massively struggling. (For social VR, it would be mixing the solved avatar IK pose with a physics simulation, maybe with an additional specialized IK pass to keep the head joined with the HMD)

I haven't yet figured out how to do accurate pose matching of rigidbodies (/ArticulationBody) while preserving inertia and avoid fighting external applied forces from the environment. I'm currently using PID controllers for limbs (pos, rot) solved in world space (no hinge motors)

Are you doing this all in @BasisVR ? This is exactly why open source is the best.

@BasisVR If we're talking about this specific video, Basis is not necessary, it's only when I need avatar loading/locomotion/VR avatar integration/shippable demos that Basis can become useful. Otherwise this video is purely Unity, there's nothing specific to Basis in this one.