A clamp on the effective world-space velocity that is passed to the simulation. Units are cm/s. The default value effectively means "unlimited". It is not usually required to change this but you would reduce this to limit the effects of drag on the physics bodies in the simulation (if you have bodies that have linear drag set to non-zero in the physics asset). Expected values in this case would be somewhat less than the usual velocities of your object which is commonly a few hundred for a character.