Collision

Animating collision involves two steps—detecting that a collision has occured between two objects and then altering their motion according to the result of the collision.

The first type of collision covered will be between round objects, which is the simplest to detect and animate. To make them bounce off each other, a spring force is used which is easily combined with other forces in the animation.

However, because of the nature of incremental animation, this method loses accuracy when the velocity of an object is large enough in relation to the distance of compression due to collision. Using a high model rate makes it possible to use spring force for most applications.

There is a second method of animating collision that doesn't use a spring force, but calculates the new trajectories mathematically and sets position and velocity directly.