Is there any way to mirror only selected parts of a shape key?

Question

I'm modifying a model and trying to add simple expressions like blinking and etc.

I'm trying to mirror a closed eye to the other side, but it causes the whole model to become symmetrical, I can't figure out how I can only mirror selected parts :|

Here's an example: https://www.youtube.com/watch?v=Qd4rqPp6hW0&feature=youtu.be

You can see his head shape and and parts of his cheeks are getting symmetrical

edit: another example, the difference between the basis shape-key and the mirrored one: https://gfycat.com/ThirdHealthyGalapagosdove

Thanks in advance!

Answer 1

When using shape keys in blender, under the settings, you can assign a vertex group to define the vertices being affected by the shape key.

Answer 2

Other answers so far are good, but it's worth pointing out another technique.

There's an easy way to restore part of a shapekey to the basis shape, using "blend from shape" operation. You can use this on parts of the mesh to "unshape" bits of the mesh.

Select the shapekey, then enter edit on the mesh. Select all vertices of the shapekey you don't want (or select the bits you do want, then select inverse.) Use a "blend from shape" operation, which I always call from the searchbar. On the operator panel, specify Basis as the shapekey, set the blend to 1.0, and disable Add. This restores the selected vertices to the Basis shape, making it so that some of your shapekey will be "unmirrored".

You can of course use this operator for a lot of other things as well.

Answer 3

Since many keys will deform the cheeks you might have to tweak the head to be symmetrical initially by deleting half the head and apply a mirror modifier. Then you can model back the asymmetrical features as a shape key to the head to bring it back to its desired shape. That is, if it is not a problem to keep the asymmetrical shape key to a value of 1 at all times.

If that is a problem then you'll need to apply that deformity to all the shape keys and the basis head so that eg: A blink left doesn't turn the head back into a symmetrical shape again.

The way I do it is turn all shape keys into individual meshes. Then copy all basis head mesh to pair with the all the shape keys mesh. All the basis heads copies get 2 keys the asymmetrical shape key and all the individual shapes like blink left key. While the basis copy head has both keys set to a value of 1 you create a shape key by selecting the basis copy head then select the original symmetrical basis head then Join as shape in the shape key's special menu.(down arrow)