Altering amarture pose causes weird deformations (.blend)

I’m having some problems rigging my chimp-like humanoid, specifically with the arms. I’ve checked to make sure all the verticies are assigned correctly, I’m pretty sure they are. The arms are almost perfectly identical so I can’t understand why one works and one doesn’t. The picture should make the problem clearer :

Any ideas ? I’m willing to post the .blend if it’ll help.
Just realized I should have posted a pic with the arms in the pose they were modelled in as well - they just hang straight down.

The problem is on the naming of your vertex groups… I am almost sure that you modeled one half, rigged, and duplicated… or when rigging you created the vertex groups by using box-selection.

The issue is that both hands are asigned the the same vertex-group. To check if this is the case: enter edit mode, make sure that there are no vertex selected, choose the vertex-group of the hand THAT IS WORKING RIGHT and click on the “Select” button… my bet is that vertex from both hands will light up.

Another situation could be that the bones for both arms are both fallowing the same IK-Target.

Posting the .blend certainly would help.

Thanks for the response. It’s a good guess, but it’s not right :wink:

I did use (some) box selection to select the verticies but I was careful to make sure the other half of the mesh was hidden. Unless I’ve accidentally missed something, each bone has only one group of verticies associated with it.
Here is the .blend, I hope it will help !

Doesn’t anyone know what’s wrong ?? I can’t go much further with a current WIP until this is fixed…

Well, your LUarm group is the whole left arm, not just the upper part.

Thank you !!! :smiley:

I feel really stoopid for missing that :expressionless:

Back to the blending…