Copyright © Scott Eaton
This sequence shows the use of corrective displacement mapping to achieve high resolution facial expression on top of a low-resolution animation mesh. The character on the left is rendered with his standard displacement map (sculpted in Zbrush) as well as a number of per-expression corrective maps, also sculpted in Zbrush. The same character on the right is rendered without the base displacement and shows only the corrective displacement mapping.
The entire pipeline for creating and rigging the facial setup was the topic of my Alias 3December workshop in 2005, titled appropriately “Corrective Displacement Maps for Facial Expressions”. Even though it is old, you can download the slides from the presentation here.