Life has been busy, but I finally had time to look into this more. It looks like whenever you tilt a bone from 0 degrees in one frame to 90 degrees a second or so later in the timeline, it does so smoothly. Also, if you rotate a bone from 0 degrees to 90 degrees, that works well, too. However, if you both tilt and rotate a bone, the tilting and rotating interact. The tilting is no longer smooth.
The attached project demonstrates this phenomena. I believe this means either:
1. It is a huge mistake for the AM2001 rig to use a single bone for both tilting the fingers and using the side effect of rotation to key other bones to rotate, since tilting and rotation affect each other in undesirable ways.
2. There may be some setting to tell the finger bone to always apply the tilting first, then the bone rotation.
Anyone have opinions on this?
Tilt_Rotate.prj