Physics on Armature

I am Trying to set up an armature with Physics. I found this neat trick wich ALMOST seems to fit all my needs:

Basically i have one seperate object, only consisting of a few verts with physics on it. Emtys are parented to the verts, and in the end those empties act as IK targets for the deforming bones. On its own this setup works perfectly fine!

But there is one Problem: When i try to incoorparate this Method into a Rig it does not always update properly.

It is hard to explain, so i made this Video to show you whats wrong:

On the Right i have a very basic character. Here the “physics” rig is seperate from the rest of the rig for the body and works perfectly fine. The “physics” rig is, as a whole, parented to the Head bone of the “body” armature.

On the left is what happens when i join the Rigs. The Base bone of the “physics” rig is parented to the Head bone. Now it wont update properly, and yes, this does show up in the final render. In looping animations there always is this jump at the first frame.

I often render animations as image sequence, so i can pause the render at any time and resume later. But every single time on the first frame rendered there is this jitter.

It does not matter if the physics are baked or not. Even when the “physics” part of the armature is not even parented to the head bone or anything else this jumping appears.

In the End i want to use a setup like this for all kinds of physics, animating floppy ears for a dog or fat-physics on an overweight character fox example. Or Bounciness on certain parts of the female anatomy. So i cant really have seperate meshes, and i cant deform one single mesh with two different armatures.

So, my question is what causes this behaviour? Or am is this a completly wrong approach? It seems the method described above works perfectly fine for all those purposes. But this Problem makes it completly impractical, sadly.

Id be real happy for all suggetions :slight_smile: