Mirror Without Weight...?

Hello everyone,

This is my first post here, feels nervous, and the question I am about to ask has brought me to this wonderful community, as searching just hasn’t produced any results. My apologies if this has been discussed already.

I have made a human model that I am planning to animate and to save the efforts I’ve drawn only a half of it for the other half to be mirrored later. I have also made “a half of a skeleton” (armature) without knowing that “X-Axis-Mirroring” could save me from all future trouble. And, in addition to all that, I have made a mistake by painting the appropriate weights (“Weight Paint” mode) for all bones of my right half of the armature before mirroring it and the model. Now when I mirror the model my “right” armature affects the “left” part of the body as well (as all weights have been mirrored too). If I mirror the armature the left part of it remains unlinked to any vertices respectively.
Is there a simple way of mirroring my right part of the body without duplicating the weight of the existing armature? I just… don’t want to do the left side again manually, as it probably won’t be symmetric anymore and it’s just a lot more work (first to remove all weights for the “left” bones manually and then to re-paint them again).
I don’t believe there is a “weight transfer” script or anything… or is there?

Any advice is welcome as I’m getting desperate with all this…

Hi St.,

There is a very simple fix to your predicament. The mirror modifier will mirror the vertex groups if you move it above the armature modifier, and make sure the other side of the armature has the exact same name with the opposite side suffix (“L” or “R”).

I made a little dummy rig to show you. I did it following the same steps you outlined, built half the armature and half the mesh and weighted them, then applied the mirror modifier (with vertex groups enabled, and moved above the armature modifier), then mirrored the arm and leg in the armature. You can easily rename any bones mirrored manually in pose mode by selecting the bones to rename and pressing “w->flip left-right names”. I never really use X-axis mirror myself because I find I always forget to turn it off! haha, and it just ends up making a mess :slight_smile: But that’s likely just me.

There are also scripts for managing vertex groups (among other things) in my signature.

Welcome to the forums!


dummy_mirror.blend (180 KB)

That’s… awesome! Thank you very much!
I’ll follow your suggestion right away. :wink: