On certain applications, specially games, it is often necessary to determine if two moving objects collide. The standard approach is to check for overlap after each step of the animation. While this approach may be sufficiently accurate for some applications, sometimes you need to determine the exact point of collision so that you can apply collision forces or handle the situation more accurately. Also, if objects are moving too fast the overlap approach may miss the collision entirely.
Here we will have a look at a predictive, or a priori, technique specially suited for particles or small objects. It detects collisions even if the bodies are moving fast and it's pretty accurate at determining the collision point.