CD
A free collision detection library. Source code, example and theory of collision detection available for download.
ColDet: Free 3D Collision Detection Library
A free library intended for game programming. Supports general polygon soups and based on bounding-box hierarchies. Open source, from The Photon Effect.
Computing the Distance between Objects
An implementation of the Gilbert, Johnson, and Keerthi (GJK) algorithm for tracking the distance between a pair of convex polyhedra. Source available for nonprofit use.
I_COLLIDE
An interactive and exact collision-detection library for convex polyhedra. Includes the source code (free for noncommercial use), relevant papers, and an MPEG demonstration.
QuickCD
General-purpose collision detection library, capable of handling general polygon soups. Based on hierarchies of bounding volumes of discrete-orientation polytopes. Free source for noncommercial use.
RAPID: Robust and Accurate Polygon Interference De
A numerically robust library supporting general polygon soups, based on oriented bounding box (OBB) trees. The source is available for noncommercial use via email. A paper on OBB trees is available for download.
SOLID: Software Library for Interference Detection
LGPL standard C++ library for interactive collision detection, based on axis-aligned bounding box trees.
V-Clip Collision Detection Library
An implementation of the Lin-Canny algorithm for computing the distance between two closed polyhedra. Source available for noncommercial use.
V-Collide
A collision detection library for general polygon soups. Combines I_COLLIDE's "sweep and prune" algorithm with RAPID. Source available for noncommercial use.