Is a collision between two circular bodies supposed to affect the rotation? Because it doesn't! At least not in my little experiment here. Things are bouncing off each other, but nothing is happening to the rotation. Am I supposed to adjust the rotation in a collision handler? I was thinking like when two pool balls collide or clip each other causing one to spin.

Thanks!

Ensure object.isFixedRotation is set to false and that should allow physics to affect rotation.

Also make sure that body.angularDamping is zero (or low value).