Nick Romick Turns UV Space Into a Sprite Sheet to Create 2D Facial Expressions for a Minifig Character in Maya.

The Lego movies sport a mix of 3D and 2D elements together in one shot. Especially the lipsync and facial features of the minifig characters. Wondering how this was accomplished, 3D Artist Nick Romick noticed that there is a lack of tutorials that would suggest how. After a bit of tinkering, he came up with a solution that uses the UV space as a sprite sheet to create a rig that can quickly switch between mouth poses and 2d facial expressions.

“I explain how to use keyed expressions to drive UV coordinates to change both the eyes and the mouth expressions all in one material,” Romick says. Moving the UV shells around to different parts of the UV space selects a new 2D facial expression. The whole thing is managed with driven keys and uses Maya’s polyMoveUV node to facilitate the moving of UV shells in UDIM space.