OK, two things!
The object spinning slows down smoothly, until it comes to a very abrupt stop. The sudden complete stop is too early, and looks unnatural for my use case. Is there some parameter which can be tweaked to affect this behavior?
This sudden stop is the deactivation (or sleeping) behaviour built into the physics engine, which stops simulating bodies which have stopped moving (or nearly stopped) - it’s possible to disable this behaviour per-body; check out lines 51-54 here:
This is an unofficial, unsupported way to disable the setting, as it isn’t currently exposed in the physicsBody properties, it’s on our list to add someday soon, but the above should work if it’s critical for your use-case.
I cannot seem to affect the angular damping below a certain point.
Nice catch! We have a default, small amount of angular damping per body for stability and it looks like we have a bug where that was still being applied, even if you set a lower one. I’ll get this fixed in the next plugin update.