FACS #2: Making Blendshapes
Updated: May 21, 2021
Last week we imported all of our blendshapes into a maya scene. We have all the expressions we need, including a "neutral" expression (it came with the head scan pack I bought).
If we try to add our "look up" expression to the neutral head as blendshape, you'll notice some unwanted deformation happening. We only parts of the geometry to move, not the whole thing! So how do fix that?
With the blendshape turned on, we'll go to the Paint Blendshape Weights tool and "weight" our blendshape, like so:
In addition to fixing that deformation, I want to divide my blendshapes into left/right sides. Using the cheekSuck expression as an example, I'll select half the vertex of the face and flood weights to zero.
I also smoothed weights so the transition wouldn't be as harsh. This example is far from perfect (especially on the chin/collar area lol) , but you get the idea:
I'm going to duplicate this and rename it to l_cheekSuck ("left Cheek Suck"). I'll go ahead and do the same for the right side. Rinse and repeat until I have a left/right for most of the blendshapes...
For some expressions such as the "face compression" (pictured right), instead of dividing it into left/right, I'll paint the weights so that the whole face still compresses but the head/neck/collar are left alone. You could make a left and right blendshape, but based on what I've seen online, most riggers have a central control that lets animators compress the whole face at once.
That's it for this week! I'm hoping to release a video next week showing how to plug these bad boys into a rig. Stay tuned and have a good rest of your week!