Abstract base class for scene hierarchy interface.
This base class defines the interface that run-times can implement to navigate the scene hierarchy, for a given scene item. The Hierarchy interface supports parent-child hierarchy semantics and queries, with the following characteristics:
- an item has a single parent, or none if it is not in a hierarchy, or is a hierarchy root.
- an item has 0 or more children. Certain DCC data models (e.g. Maya) allow objects to have multiple parents in the case of instancing. This does not affect UFE single-parent semantics. The different UFE paths to a Maya instanced object uniquely identify each instance, in exact correspondence to how a Maya MDagPath uniquely identifies the instance to Maya.
To avoid the memory-consuming "one proxy object per scene object" approach, Hierarchy interface objects should be obtained and used within a local scope, and not stored. Hierarchy interfaces should be considered stateless, and can be bound to new selection items.
Definition at line 64 of file hierarchy.h.