Well, I try to mess up around with transform constraint but didn't seem to understand how to do it properly (some time I made it and some time I didn't). Still dont know how tris reverse rotate thing anyway because the tutoral video didn't show if we can do it or not with transform constraint

Nate wrote

You can set the transform constraint rotate mix to -100.
Transform constraints - Spine User Guide: Mix
Constraints: Mix

The -100 rotate mix didn't work , those two bone still rotate in the same way, and the video didn't showing any working example of Reverse rotate either.

Thank for the detail explain. But my case seem like working different way and I dont really know how it work, kinda randomness.
(Some bone rotate alot while the other rotate so little) Could you explain my situation and how to make it work more consistent?:

You can check out the project in the attachment file down here>>>>>>>>

Nate wrote

You have keys that set the rotate mix to 0, -31.4, 36.4, and 0. Why? Set it to -100.

I understand it now,
Reverse rotate with -100 rotate mix only make the target bone reverse from the rest.
So this should be a nice way to work with muscle:

Thank you for your help. This is a good way to control muscle

Erika wrote

If you're looking for ways to animate muscles and shoulders, here are a couple of tips that may also be useful:
Spine Tips: 4 shoulder
Spine Tips: 1 muscles

Thank you, those tips are really a great help to me :fiesta: