Blendshape Facial Animation

Abstract

Blendshapes are a standard approach for making expressive facial animations in the digital production industry. The blendshape model is represented as a linear weighted sum of the target faces, which exemplify user-defined facial expressions or approximate facial muscle actions. Blendshapes are therefore quite popular because of their simplicity, expressiveness, and interpretability. For example, unlike generic mesh editing tools, blendshapes approximate a space of valid facial expressions. This article provides the basic concepts and technical development of the blendshape model. First, we briefly describe a general face rig framework and thereafter introduce the concept of blendshapes as an established face rigging approach. Next, we illustrate how to use this model in animation practice, while clarifying the mathematical framework for blendshapes. We also demonstrate a few technical applications developed in the blendshape framework.