Practical and Realistic Facial Wrinkles Animation

Virtual characters in games are becoming more and more realistic, with recent advances for instance in the fields of skin rendering [d’Eon and Luebke 07, Hable et al. 09, Jimenez and Gutierrez 10] or behavior-based animation [NaturalMotion 05]. To avoid lifeless representations and help the user engage in the action, more and more sophisticated algorithms are being devised that capture subtle aspects of the appearance and motion of these characters. Unfortunately, facial animation and the emotional aspect of the interaction have not been traditionally pursued with the same intensity. We believe this is an important missing aspect in games, especially given the current trend of story-driven AAA games and their movie-like real-time cutscenes. Without even realizing it, we often depend on the subtleties of facial expression to give us important contextual cues about what someone is saying, thinking or feeling. For example, a wrinkled brow can indicate surprise, while a furrowed brow may indicate confusion or inquisitiveness. In the mid-1800s, a French neurologist named Guillaume Duchenne performed experiments that involved applying electric simulation to his subject’s facial muscles. Duchenne’s experiments allowed him to map which facial muscles were used for different facial expressions. One interesting fact that he discovered was that smiles resulting from true happiness not only utilize the muscles of the mouth, but also those of the eyes. It is this subtle but important additional muscle movement that distinguishes a genuine happy smile from an inauthentic or sarcastic smile. What we learn from this is that facial expressions are complex and sometimes subtle, but extraordinarily important in conveying meaning and intent. In order to allow artists to create realistic, compelling characters we must allow them to harness the power of subtle facial expression. We present a method to add expressive animated wrinkles to characters, helping enrich stories through subtle visual cues. Our system allows the animator to independently blend multiple wrinkle maps across regions of a character’s face. We demonstrate how combining our technique with state-