The True Axis Physics SDK features swept collision detection giving it the ability to handle rapid paced action better then other physics systems. The SDK is ideal for games that rely on fast moving vehicles or missiles.

Traditionally, physics and collision systems rely upon testing if two objects are intersecting at any given time to determine when collisions occur. If objects are moving very fast, by the time a collision is detected, the objects will often already be deeply intersecting each other. Even worse, it is possible for objects to pass through each other with no collision being detected at all.

One method to cope with this is to increase the frequency of collision testing to give the system more chance of preventing intersection. Unfortunately this is processor intensive and will always allow at least some intersection between objects.

The True Axis Physics SDK makes use of a different method: Swept collision testing. The SDK actually tests the entire movement for collisions rather then just its end point. This way all collisions are detected before they occur and can be dealt with appropriately.

Swept collision testing is more complex then intersecting collision testing but doesn't have to be done as frequently so can actually save processor overhead as well as giving a more solid response. For slow moving objects, swept collision testing is turned off with no overhead.

Swept "collision testing" vs "intersection testing only" for an object rapidly falling towards the ground.

Traditional intersection collision testing	True Axis Physics SDK Swept collision testing.
When only testing for intersections between objects, it is possible for the object to never register a collision with the ground and hence fall through.	When doing swept collisions, the collision is detected before it happens allowing the objects response to be handled appropriately.