We present a method for stably simulating stylized curly hair that addresses these artistic needs and performance demands. To satisfy the artistic requirement of maintaining the curl's helical shape during motion, we propose a hair model based upon an extensible elastic rod. We introduce a method for stably computing a frame along the hair curve, essential for stable simulation of curly hair. Our hair model uses a spring for controlling the bending of the curl and another for maintaining the helical shape during extension. We also address performance concerns often associated with handling hair-hair contact interactions by efficiently parallelizing the simulation. To do so, we present a technique for pruning both hair-hair contact pairs and hair particles.
Our method has been used on two full length feature films and has proven to be robust and stable over a wide range of animated motion and on a variety of hair styles, from straight to wavy to curly. It has proven invaluable in providing controllable, stable and efficient simulation allowing our artists to achieve their desired performance even when facing strict scheduling demands.
Additional materials: [tazVideo-SCA.mov]
Available in the Proceedings of the Symposium on Computer Animation 2013.
Available as Pixar Technical Memo #12-03b