Makes the collision detection system ignore all collisions between
This is useful, say, for preventing projectiles from colliding
with the object that fires them.
IgnoreCollision has a few limitations: 1) It is not persistent. This means ignore collision state will not be stored in the editor when saving a scene. 2) You can only apply the ignore collision to colliders in active game objects.
See Also: Physics.IgnoreLayerCollision.