## R

reference count
  A control for a component object model (COM) object. When an object is created, its reference count is set to 1. Every time an interface is bound to the object, its reference count is incremented; when the interface connection is destroyed, the reference count is decremented. The object is destroyed when the reference count reaches 0. All interfaces to that object are then invalid.
root frame
  A frame in Direct3D that has no parent frame; a frame at the top of a hierarchy of frames. The root frame contains the entire set of objects that make up a scene. See also scene.