Reliable Contact Simulation With IPC

Simulating the contact of deformable and possibly thin solids in a robust, accurate, and efficient manner is challenging. Traditionally, the contact of solids is approximately modeled with linearized geometric information near the contacting regions. This approximation is prone to generating underconstrained or overconstrained subproblems that can produce interpenetrating or numerically unstable results, especially when large deformation of solids is also present. To avoid these issues, we propose incremental potential contact (IPC) by formulating a mathematically consistent and general noninterpenetration constraint based on precisely calculated unsigned distances between boundary elements. IPC applies a customized barrier potential to directly relate the distances to the contact forces, which can grow infinitely large as the distance approaches zero to guarantee noninterpenetration. Results show reliable contact simulation even with versatile materials, large timestep sizes, fast impact velocities, severe deformation, and varying boundary conditions-bringing the intricate and important dynamical details to computer graphics in a reliable way for the first time.