Disney's Hair Pipeline: Crafting Hair Styles From Design to Motion

In this talk we will describe the hair pipeline utilized on Disney’s most recent full length animated feature, Frozen. Producing intricate hair styles is a challenging problem, spanning many departments. We focus on the generation of the hair groom and motion. This process starts by producing the groom, guided by 2D artwork from visual development and 3D proxies from modeling. We have developed a new intuitive interactive grooming tool, Tonic, which uses geometric volumes to procedurally groom the hairstyle. Once the hair volumes are sculpted, Tonic generates a set of guide curves within each Tonic hair tube. These tubes and guide curves are then passed to simulation which produces motion for a subset of the guide curves. The motion is controlled using an animation rig and a two-level simulation rig with the underlying dynamics calculated using our in-house solver. This motion is then mapped onto the full set of guide curves. In technical animation, cleanup and fine-tuning of the motion is done on a per-shot basis. Finally, the guide curves are interpolated and extra detail added using XGen, to produce the final set of curves sent to rendering. With this new workflow and toolset, the artists were able to create the almost 50 unique hair styles on Frozen.