I was wondering if this would be of interest to anyone else. I thought it might be a cool feature to suggest to the developers of Blender, but I have relatively little experience, and I thought I’d see if anyone else found it interesting or had suggestions. I thought of this as a potential for customizing bone/joint constraints visually. It might work well for rigging from a sort of animatic approach.
On the video, the bright green zones allow for rotation, the rest are constraints. To add rotation allowance, users would paint more faces of each corresponding shape, or make their own and paint them.
Example 1 shows a hinged joint. Extruding the circular plane would allow for some sloppiness in the hinge. A knee or elbow would probably work as a circular plane, but a knuckle of the hand would probably be an extrusion (short cylinder).
Example 2 would be a rotator cuff style joint.
Example 3 would be a “traveling,” sliding-rotator style joint.
These came to mind while stumbling through a recent rigging exercise (for my own study). Sorry for the slight delays between examples, slapped this together quickly. Yes, that title is a joke, but I thought the idea worth posting.