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 [method CharacterBody2D.move_and_slide] for improving floor detection when floor snapping is disabled.
If set to [code]false[/code], only collisions resulting from the motion are reported; this is used e.g. by [method PhysicsBody2D.move_and_collide].