The combination of a cluster and blend shape
is ideal for facial animation because it lets you tune various subtle
deformations. A few common techniques follow.
In
the box below the slider of the Blend Shape editor,
you can enter a numerical value below 0 to invert the deformations,
or above 1 to amplify the deformations. For example, -1 creates
a frown, while 1.6 creates a brimming smile:
With
or without changing the Blend Shape slider,
you can move, rotate, and scale the cluster handle to modify the
blend shape. The following figure shows some examples. The face
you created will be slightly different because your original smile
is different.
You
can use the Paint Cluster Weights tool
again to change cluster weights when the cluster and blend shape
editing deforms certain regions undesirably or doesn’t give the
exact look you desire. You can also use Ctrl - Z (Windows and Linux)
or Control-z (Mac OS X) to undo any undesired changes.