Hayley Iben, Mark Meyer, Lena Petrovic, Olivier Soares, John Anderson, Andrew Witkin
We present a novel method for stably simulating stylized curly hair that addresses artistic needs and performance demands, both found in the production of feature films. 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 novel method for stably computing a frame along the hair curve, essential for stable simulation of curly hair. Our hair model introduces a novel 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 novel algorithm for pruning both hair-hair contact pairs and hair particles. Our method is in use on a full length feature film 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.
Available as Pixar Technical Memo #12-03a