Collision Detection is the checking or detection for and of objects touching, intersecting, or hitting, or in someway making contact in the computer based simulated world. The topic of Collision Detection very often relates to Graphics Programming. Computer Based Modelling (of physics) is often part of Graphics Programming; and Collision Detection is often part of that Computer Based Modelling.
Software for detecting collisions among geometric objects. Most of the software provide complete collision detection, allowing objects to move dynamically while detecting collisions among them. Other software is just for the static case: do polyhedra collide; if so, by how much do they penetrate; and if not, how far away from each other are they? Much of the software supports general "polygon soups": an arbitrary set of polygons in 3-D (typically triangles) with no connectivity information required. Other software exploits the structure of special objects, such as convex polyhedra.