[maplant]

This is the basis for basically every physics engine in some form of another. Collision is divided into the "broad phase" pruning step that typically uses the bounding box of an object and a "narrow phase" collision detection step that uses the more detailed collision primitives

[tarnith]

also how raytracing works with bounding volume hierarchies

and how occlusion culling worked with BSP trees in Quake if I remember correctly as well