swapping face textures for expressions?

I’d like to know if it is possible to swap a number of textures to express emotions and/or lip-syncing on a 3d model. like traditional animation on the face. that’s the best way i can explain it. swapping textures on a model. is this possible? if so, a pointer to a tutorial or relevant manual pages would be greatly appreciated. i am using, at the moment, unity free, latest download 4.6.1f1 , blender or maya lt 2015, gimp, etc.

There are a couple ways I can think of solving this.

  1. Create a number of different materials, swap the materials on the MeshRenderer every time you need to update the face.
  2. Create a texture sheet of multiple expressions. Procedurally “scroll” the UVs of the character face geometry.

I came across this blog post the other day which has an interesting breakdown of how 2d eyes are animated on 3d models in Legend of Zelda Twilight Princess - includes a sample Unity package which you might find useful: Twilight Princess Eyes Breakdown « Ben Jones

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