When you create a garbage mask, an Axis node and a Geom node are added to the schematic. The Axis node contains rotation, position and scaling data. The Geom node contains information about how the mask will affect the image. There is also a Camera node, which is always part of the scene. The Camera node can parent the Axis node for greater precision over the garbage mask, particularly if you want to rotate or orbit the camera with respect to the garbage mask.
To view the schematic, select Schematic from the World View box or press Tilde (~) to toggle between the Schematic view and the previous view.
(a) Axis node (b) Geom node
For information on working with the schematic, see Schematic Basics.