Real-Time Collision Detection

Chapter 12

Geometrical Robustness

Just as it is important with numerical robustness, it is important for collision geometry on which tests are performed to be well formed. If not, the presence of small cracks between neighboring faces could cause objects to fall through what is intended to be solid. In fact, several geometrical features may cause problems for collision detection code, including the following.

• Redundant vertices, edges, and faces

• Degenerate faces, including nonconvex or self-intersecting faces and faces of zero or near-zero area

• Incorrect orientation of single-sided faces

• Unintended holes, cracks, gaps, and t-junctions between neighboring faces

• Nonplanar faces

In addition, interpenetrating faces may or may not present a ...