Losing Limbs: detaching body parts in the middle of a simulation


I’m exploring using ragdoll for some game animations of robots getting a limb destroyed and subsequently falling in a way that makes sense with the sudden loss of balance. Is there any way to have a limb detach partway in a simulation so that they would lose balance in a way that makes sense? What would be your suggestions for this?

Welcome to the forums @g6k :partying_face:

You can achieve this effect by animating Translate Motion and the Translate/Rotate Stiffness attributes on the Marker you want to detach.


The Translate Motion attribute controls how the arm should be attached, and Stiffness controls how strongly it should follow your animation. In the case of detaching limbs, you’ll want none of that.

The limitation to this approach however is that even though the arm is detached, the limits will still be active, and they cannot be animated on/off. So for any limb you need detached, you may also need to disable limits from the start. Otherwise, their rotation will still be limited as though it was still attached, which may or may not be an issue.

See here for example the same scene, but with limits on arms and legs still enabled.

See how the arm starts to fling unprovoked?

Hope it helps!


Great, that perfectly did the trick for my tests. Thank you!