If set to [code]true[/code], shapes of type [constant PhysicsServer2D.SHAPE_SEPARATION_RAY] are used to detect collisions and can stop the motion. Can be useful when snapping to the ground.
If set to [code]false[/code], shapes of type [constant PhysicsServer2D.SHAPE_SEPARATION_RAY] are only used for separation when overlapping with other bodies. That's the main use for separation ray shapes.
If set to [code]true[/code], any depenetration from the recovery phase is reported as a collision; this is used e.g. by [CharacterBody2D] for improving floor detection during floor snapping.
If set to [code]false[/code], only collisions resulting from the motion are reported, which is generally the desired behaviour.