Fast GPU-Based Two-Way Continuous Collision Handling

TL;DR

This paper introduces a fast, robust GPU-based two-way collision handling method for deformable bodies that improves safety and efficiency in simulations with large deformations or time steps.

Contribution

It proposes a novel two-way optimization approach that interleaves forward and backward steps to reliably handle continuous collisions across various deformable bodies.

Findings

Method is safe and robust for large deformations.

Achieves high efficiency with large time steps.

Handles diverse deformable bodies like volumetric, cloth, hair, and sand.

Abstract

Step-and-project is a popular way to simulate non-penetrated deformable bodies in physically-based animation. First integrating the system in time regardless of contacts and post resolving potential intersections practically strike a good balance between plausibility and efficiency. However, existing methods could be defective and unsafe when the time step is large, taking risks of failures or demands of repetitive collision testing and resolving that severely degrade performance. In this paper, we propose a novel two-way method for fast and reliable continuous collision handling. Our method launches the optimization at both ends of the intermediate time-integrated state and the previous intersection-free state, progressively generating a piecewise-linear path and finally reaching a feasible solution for the next time step. Technically, our method interleaves between a forward step and a backward step at a low cost, until the result is conditionally converged. Due to a set of unified volume-based contact constraints, our method can flexibly and reliably handle a variety of codimensional deformable bodies, including volumetric bodies, cloth, hair and sand. The experiments show that our method is safe, robust, physically faithful and numerically efficient, especially suitable for large deformations or large time steps.