Super-Helices for Predicting the Dynamics of Natural Hair

Florence Bertails (1) , Basile Audoly (2) , Marie-Paule Cani (1) , Bernard Querleux (3) , Frédéric Leroy (3) , Jean-Luc Lévêque (3)

1 EVASION - Virtual environments for animation and image synthesis of natural objects
2 DALEMBERT - Institut Jean Le Rond d'Alembert
3 L'Oréal Recherche - L'Oréal Recherche France

Simulating human hair is recognized as one of the most difficult tasks in computer animation. In this paper, we show that the Kirchhoff equations for dynamic, inextensible elastic rods can be used for accurately predicting hair motion. These equations fully account for the nonlinear behavior of hair strands with respect to bending and twisting. We introduce a novel deformable model for solving them: each strand is represented by a Super-Helix, i.e., a piecewise helical rod which is animated using the principles of Lagrangian mechanics. This results in a realistic and stable simulation, allowing large time steps. Our second contribution is an in-depth validation of the Super-Helix model, carried out through a series of experiments based on the comparison of real and simulated hair motions. We show that our model efficiently handles a wide range of hair types with a high level of realism.

Domaines: Synthèse d'image et réalité virtuelle [cs.GR]

Florence Bertails, Basile Audoly, Marie-Paule Cani, Bernard Querleux, Frédéric Leroy, et al.. Super-Helices for Predicting the Dynamics of Natural Hair. ACM Transactions on Graphics, 2006. ⟨inria-00384718⟩