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So I am modelling something for a friend. Its a cat from a game and it has some little bells on a collar.

enter image description here

I modelled and textured everything, and I was able to use Rigid Bodies for the bells so they move with the cat. But once I rigged the cat the rigid bodies don't follow the cat anymore

I attatched them using a Generic rigid body constraint with empties connecting the cat mesh to the bells. I also have strings connecting the cat to the bells using the Hook modifier, but I have been able to figure that out.

I just can't seem to find a way to make the rigid bodies follow the deformations of the rig.

Setup

Here is how I attached everything. The best that I have been able to get is the empties to follow the rig, but the rigid body simulations don't follow with the empties that are constraining them.

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I've done.

Youtube:

First of all - seems that rigid bodies aren't working with armature-deformed meshes directly. But with some intermediate objects it is possible to make them. I made the chain: rigid proxy object ("fake tip") and ball constrainted by empty ("joint"), this empty is child of "fake tip", "fake tip" is child of last bone in armature. Also armature constrainted with IK and deforms mesh ("tentacle").

Looks like you have to place additional rigid proxy objects for every bone where could be collision with other rigid bodies.

I made some different attempts with different combinations and only this one works for me. But hope somebody could make it simplier.

Added some screenshot: enter image description here

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  • $\begingroup$ could you give a more detailed explaination and a few screenshots? (I think this answer will still be useful in the futur) $\endgroup$ – Bithur Jul 17 '15 at 15:17
  • $\begingroup$ I don't know how to explain more after what I wrote and attached scene. I just made simple armature-controlled object, one simple mesh which is repeating form of tip of that "tentacle", and one spehere. Then I linked that tip to the last bone in armature and linked one empty to it. Then I made tip and ball rigid bodies and added empty as point constraint between them. Then I made armature IK-controlled by additional empty (actually it doesn't matter), made some animation, and after all baked rigid bodies simulation. Finish. $\endgroup$ – Daniil Romanov Jul 17 '15 at 19:23
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Well. You can create two rigid bodies, one passive animated one (perhaps a lowres of your character or a dummy parented to it) and the rigid body you wish to simulate. Then create a generic spring rigid body constraint between them. I'm not certain you can create an animated passive rigid body from an empty, but if not you could create a plane, use box collision and set it to not render.

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