Maya Blendshapes not deforming correctly

Jhburton

Hey everyone,

I'm having a weird issue I was hoping someone could help me with.

I'm doing corrective blendshapes for a joint based facial rig, and I'm having an issue where the corrective blenshape is deforming the mesh in an unexpected way - basically, it modifies some verts that aren't supposed to be moving.

I should point out that the "rogue" verts that are modified are always the same ones, in exactly the same way, regardless of the blendshape applied.

I've attached some images to help understand the issue a little better (note that I used an example that would be very obvious and not an actually usable deformation!).





As you can see I highlighted the verts that shouldn't be moving, but do so when I apply the blendshape. The SAME verts move regardless of the blendshape mesh i apply

In terms of the deformation order I'm using, it's set to "front of chain" - interestingly, the rogue verts are only affected when I use this method - if I use "default", the issue doesn't occur, however I can't use this method since when it is used to correct an already deformed mesh (ie: to correct an open jaw), it deforms it back to the full corrective difference pose.

Can anyone help me out with this?

Jhburton

Managed to solve the issue in the end. I was able to use the Default blendshape mode and using the mesh inputs menu (Right click on mesh - Inputs - All inputs) I moved the Blendshape node to be above the skin cluster. This way I can pose the face and then add the blendshape without going back to the full corrective pose and only affect the verts affected.

Hope this helps anyone with the same issue!

Takecake

I had the exact same issue you did and was unable to solve it with your method. Just for the records though, what ended up working for me was duplicating the skinned mesh, re-skinning it, copying the skin weights from the original mesh with problems to the new duplicate, and then adding the blendshapes I did for the original mesh to the duplicate, and it worked without the weird unnecessary rogue deformations.