USD stage composition

A stage is a USD root file and all of its layers. In Maya, the equivalent term to a stage is a scene. In Maya we "load" a scene, but in USD we "compose" a stage. A composed stage is a hierarchy of prims that represent scene elements like characters, lighting, etc.

Composition arcs

Composition is the process of assembling multiple layers together through compositions arcs, which relate layers to each other. The result is a stage of USD prims. Composition occurs when you open a stage, load or unload prims on a stage, or edit layers that contribute to the stage. Composition arcs are the "operators" that enable USD to create compositions of many layers. There are six kinds of arcs: sublayers, inherits, variant sets, references, payloads, and specializes. In all arc types, stronger layers override weaker layers.

LIVRPS strength ordering

LIVRPS describes the strength ordering in which the various composition arcs combine within each layer stack.

Related Concepts: The USD stage workflow in the Outliner and USD Layer Editor is unique to Maya, but it's based on concepts that are explained in the Pixar USD glossary. If you're new to USD, you can get started by learning about relevant terms including, stage, stage traversal, prim, composition, composition arcs, LIVRPS strength ordering, opinions, and references.