Our approach models hair as a infinitesimally thin elastic rod, similar to prior work (eg. [Bergou et al. 2008; Bergou et al. 2010]). We represent a single hair by a piecewise linear curve and calculate a material frame for each point. Our force model must satisfy three properties to create our desired visual looks. First, we desire relatively inextensible hair rods, allowing artistic control over stretch. Second, we want a hair model that holds an arbitrary curl’s shape while allowing it to flex with motion. Last, we want our curls to reasonably maintain their initial shape during motion, avoiding curl unwinding.