A helper node, mostly used in 3rd person cameras. The SpringArm3D node is a node that casts a ray (or collision shape) along its z axis and moves all its direct children to the collision point, minus a margin. The most common use case for this is to make a 3rd person camera that reacts to collisions in the environment. The SpringArm3D will either cast a ray, or if a shape is given, it will cast the shape in the direction of its z axis. If you use the SpringArm3D as a camera controller for your player, you might need to exclude the player's collider from the SpringArm3D's collision check. Adds the [PhysicsBody3D] object with the given [RID] to the list of [PhysicsBody3D] objects excluded from the collision check. Clears the list of [PhysicsBody3D] objects excluded from the collision check. Returns the spring arm's current length. Removes the given [RID] from the list of [PhysicsBody3D] objects excluded from the collision check. The layers against which the collision check shall be done. See [url=https://docs.godotengine.org/en/latest/tutorials/physics/physics_introduction.html#collision-layers-and-masks]Collision layers and masks[/url] in the documentation for more information. When the collision check is made, a candidate length for the SpringArm3D is given. The margin is then subtracted to this length and the translation is applied to the child objects of the SpringArm3D. This margin is useful for when the SpringArm3D has a [Camera3D] as a child node: without the margin, the [Camera3D] would be placed on the exact point of collision, while with the margin the [Camera3D] would be placed close to the point of collision. The [Shape3D] to use for the SpringArm3D. When the shape is set, the SpringArm3D will cast the [Shape3D] on its z axis instead of performing a ray cast. The maximum extent of the SpringArm3D. This is used as a length for both the ray and the shape cast used internally to calculate the desired position of the SpringArm3D's child nodes. To know more about how to perform a shape cast or a ray cast, please consult the [PhysicsDirectSpaceState3D] documentation.