Bounce Maps:
An Improved Restitution Model for Real-Time Rigid-Body Impact

We present a novel method to enrich standard rigid-body impact models with a spatially varying coefficient of restitution map, or Bounce Map. Even state-of-the art methods in computer graphics assume that for a single rigid body, post- and pre-impact dynamics are related with a single global, constant, namely the coefficient of restitution. We first demonstrate that this assumption is highly inaccurate, even for simple objects. We then present a technique to efficiently and automatically generate a function which maps locations on the object’s surface along with impact normals, to a scalar coefficient of restitution value. Furthermore, we propose a method for two-body restitution analysis, and, based on numerical experiments, estimate a practical model for combining one-body Bounce Map values to approximate the two-body coefficient of restitution. We show that our method not only improves accuracy, but also enables visually richer rigid-body simulations

• Paper [high quality (72M)] [compressed (3.7M)]
• Presentation [Keynote (401M)]
• Supplemental Video [high quality (233M)]

Jui-Hsien Wang, Rajsekhar Setaluri, Doug L. James, and Dinesh K. Pai. Bounce Maps: An Improved Restitution Model for Real-Time Rigid-Body Impact. ACM Trans. Graph. 36, 4, Article 150 (July 2017)

BounceMap Viewer: restitution-www

This WebGL-based viewer allows you to view BounceMap for the 3D models provided in the paper. BounceMap computed for the smooth objects are displayed as textures on the model directly. For the non-smooth objects (restitution value as function of both position and contact normal), please use the offset-point shading method in the viewer. For more details, please refer to the paper.

• NSERC
• Canada Research Chairs Program
• Adobe Research
• Mitsuba Renderer