3D separation ray shape to be added as a [i]direct[/i] child of a [PhysicsBody3D] or [Area3D] using a [CollisionShape3D] node. A ray is not really a collision body; instead, it tries to separate itself from whatever is touching its far endpoint. It's often useful for characters.
[b]Performance:[/b] Being a primitive collision shape, [SeparationRayShape3D] is fast to check collisions against.