Efficient Elasticity for Character Skinning with Contact and Collisions


We present a new algorithm for near-interactive simulation of skeleton driven, high resolution elasticity models.

August 7, 2011



Aleka McAdams (Walt Disney Animation Studios/University of California, Los Angeles)

Yongning Zhu (PDI/DreamWorks)

Andrew Selle (Walt Disney Animation Studios)

Mark Empey (Walt Disney Animation Studios)

Rasmus Tamstorf (Walt Disney Animation Studios)

Joseph Teran (University of California, Los Angeles/Walt Disney Animation Studios)

Eftychios Sifakis (University of Wisconsin, Madison/Walt Disney Animation Studios)

Efficient Elasticity for Character Skinning with Contact and Collisions


Our methodology is used for soft tissue deformation in character animation. The algorithm is based on a novel discretization of corotational elasticity over a hexahedral lattice. Within this framework, we enforce positive definiteness of the stiffness matrix to allow efficient quasistatics and dynamics. In addition, we present a multigrid method that converges with very high efficiency. Our design targets performance through parallelism using a fully vectorized and branch-free SVD algorithm as well as a stable one-point quadrature scheme. Since body collisions, self-collisions and soft-constraints are necessary for real-world examples, and we present a simple framework for enforcing them. The whole approach is demonstrated in an end-to-end production-level character skinning system.

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