Teaches how to create a dynamic material that is driven by a vector parameter. This is part 1. Part 2 will show how to drive the material through Matinee.
http://www.fileplanet.com/218746/210000/fileinfo/UT3-Head-and-Textures
EDIT: Somebody pointed out to me that you could just use a Linear Interpolation (Lerp) node instead of doing the one minus stuff, but either way works fine.
