
444 Chapter 8 Collision Detection
8.2 Finding Collisions between
Moving Objects
This section describes the mathematics for determining the first time of contact be-
tween two convex objects, each mov ing with a constant linear velocity. Although the
paths of motion for the objects are usually not linear—the objects can have nonzero
angular velocity—the paths may be decomposed into approximating subpaths. On
each subpath the object is assumed to have constant linear velocity and zero angular
velocity. The subpaths are a natural outcome of solving the differential equations of
motion for the objects.
8.2.1 Pseudodistance
The algorithm presented here is