Having a problem with Mirror Shape Key

Support Animation and Rigging
1

I’m following a tutorial on creating and rigging a character, and I’ve hit a wall with mirroring shape keys.

Basically, when I attempt to mirror shape keys (on the eye lids), I get an error that some of the vertices failed, e.g. “5050 vertices mirrored, 44 failed.”

Here’s how I’m attempting to mirror the shape keys:

STEPS

  • set the influence of the shape key I’m mirroring to 1, and all other shape keys to 0
  • with my shape key selected, “New Shape From Mix”
  • with the new shape key selected “Mirror Shape Key” (also tried “Mirror Shape Key Topology”, same problem)

EXPECTED

New shape key should mirror the old one

ACTUAL

After error, “5050 vertices mirrored, 44 failed”, new shape key is mosty mirrored correctly, but applying it affects a mix of vertices on the left and right eyes.

PLATFORM:
MacOSX 10.10.5
BLENDER 2.7.5a

The result is that my mirrored shape key has left those “failed” vertices on the original side, so that when you, say, try to open the top eye lid of the right eye, it mostly opens there, but some vertices stick on the right side and move on the right.

I’m pretty confident that the model I’m working with is symmetrical across the X axis. I created the model with a mirror modifier and any sculpting I did since, I did with x-mirror enabled.

That being said is this a common problem/is there any straightforward way to “fix” my model so that I can mirror these shape keys?

The only thing I could think to do would be ensure my model is symmetrical by cutting it in half and remirroring it, but that would be a hassel because blender won’t allow me to mirror the model while it has shape keys.

Any help with this is greatly appreciated!

2

I had the exact same problem. I started over again using small simpler shapes, and here’s what I found:

Even though I had the exact same verts and they were originally mirrored, Mirror Shape Key wouldn’t work; in my case, all the verts failed to copy.

To fix it, I had to delete all the shape keys, then delete the left half of my model, use the mirror modifier across the X axis, and then apply it, and then make no further changes to the model – only then would the Mirror Shape Key actually work successfully.

Apparently, the vertices need to be mirrored across the X axis EXACTLY for blender to find the matching verts. Even the tiniest of adjustments and the Mirror Shape Key will fail.

Hope that helps.