The Rigidbody's collision detection mode.
Use this to set up a Rigidbody's for continuous collision detection, which is used to prevent fast moving objects from passing through other objects without detecting collisions. For best results, set this value to CollisionDetectionMode.ContinuousDynamic for fast moving objects, and for other objects which these need to collide with, set it to CollisionDetectionMode.Continuous. These two options have a big impact on physics performance. Alternatively, you can use CollisionDetectionMode.ContinuousSpeculative, which is generally cheaper and can also be used on kinematic objects. If you don't have issues with collisions of fast objects, leave it set to the default value of CollisionDetectionMode.Discrete. Continuous Collision Detection is only supported for Rigidbodies with Sphere-, Capusle- or BoxColliders. Additional resources: CollisionDetectionMode.