Hierarchical Position Based Dynamics

Abstract

The Position Based Dynamics approach (PBD) recently introduced allows robust simulations of dynamic systems in real time. The simplicity of the method is due to the fact, that the solver processes the constraints one by one in a Gauss-Seidel type manner. In contrast to global Newton-Raphson solvers, the local solver can easily handle non-linear constraints as well as constraints based on inequalities. Unfortunately, this advantage comes at the price of much slower convergence. In this paper we propose a multi-grid based process to speed up the convergence of PBD significantly while keeping the power of the method to process general non-linear constraints. Several examples show that the new approach is significantly faster than the original one. This makes real time simulation possible at a higher level of detail in interactive applications such as computer games.