Index Making Pictures

Collision Detection

Detecting when a complex moving object collides with another object is quite tricky. Doing it in real-time is even trickier. The basic problem is that it is not realistic to check every part of the geometry of an object with every other piece of geometry in the scene. Typical methods involve a simple shape which encloses the moving object - perhaps a bounding box - and testing this against parts of the scene known to be nearby. Sometimes this gives the wrong result.

In the above picture, the warrior (left) is animated to chase Lara Croft (right) and attack her. In this case, the game thinks that the warrior is the other side of the wall and won't let him turn towards Lara. He simply runs on the spot, trapped half in the wall, so she can walk past without being attacked.

Here is a similar problem. This time the horse - which continues to galop - is trapped by the corner and does not move.

Here is an example in which Lara herself is trapped. The game believes she is inside the crate (which should not be possible) and won't let her move. The only solution to this one is to reload the game.