Facial Expressions as Volumetric Deformation and Displacements

I was working through The Artist’s Complete Guide to Facial Expression by Gary Faigin. Pretty thorough book, and the facial landmarks for different expressions are well detailed. Except that I was still having problems inventing expressions. I mean, yeah, expressions can vary a lot, but I think what I was looking for was a system using which one could ‘generate’ expressions on demand, without having to copy from something.
The problem I see with copying is that I’d end up copying the facial characteristics of the subject I’m copying as well, which hardly bodes well for the (imaginary) face I’ve cooked up. And yes, it wouldn’t affect my drawing that much, but I was still unsatisfied with that idea.
This afternoon, an idea struck me: what if I used the same system I use to generate poses to generate expressions? If you really think about it, the face is just a bunch of muscles with fat over them with the layering of skin. If I could figure out the forms at the appropriate resolution, these forms could be blobs which could be displaced/deformed at will to generate expressions. Boundaries of jostling blobs basically become potential creases and wrinkles. Blobs which get squeezed on all sides by other forms bulge out.
The idea seems to be working.

The basic technique involves breaking up the ‘neutral’ face into the ‘forms’. These forms may or may not correspond to muscles, but they exist.
The next step is to decide what expression to generate. This I do by making that face myself. Once I’m satisfied that my expression is close enough to what I want in my drawing, I get back to paper.
After this, for each of the forms I’ve broken up the face into, I trace the corresponding motion that that form takes when I make that expression on my face. Just lightly touching the general area with your finger and making the expression is enough to give you a sense of which direction the blob is ‘stretching’ or ‘moving’. That’s usually enough to move that blob around on paper. Once done with all the blobs, generating the expression is surprisingly easy.

I’m still refining the form system. Here are some examples of the things you can do with this volumetric approach.

The Expressions gallery is up now.