Mark Hessler, Jeremie Talbot
Abstract:
Unsimulated character animation of items like ropes or snakes is challenging in the amount of articulation required and the degrees of freedom needing control. At Pixar we developed a powerful new system for animating highly directible curves: AutoSpline. This system is designed to give animators enormous control, without the overhead of managing every aspect of every control when only simple shapes or motions are required.
We accomplished this by providing the ability to switch sets of controls between manual and automatic modes on a frame-by-frame basis. Controls can also be dynamically repositioned per frame so that animators can focus the available controls where highest detail is needed for any given shape or motion. The AutoSpline architecture also includes advanced constraint abilities, simplifying historically difficult interactions between the flexible object and other objects in the scene.
While these features made it feasible to animate the many-tentacled Hank in Pixar's Finding Dory as a primary character, AutoSpline was built as a general solution. Early versions were successfully used in Pixar's Inside Out and The Good Dinosaur. Notably, it inspired a similar tool at ILM, used on Star Wars: The Force Awakens.
Paper (PDF)
SIGGRAPH Talks 2016