It’s often useful to define your own metadata on a USD prim or property. Metadata is a strongly typed, light-weight, extensible, and non time-varying way to describe a scene. It’s important to note that metadata cannot have its own metadata, and since metadatum can only have a single value, it is not able to be sampled over time. This contrasts with schema-defined metadata, which can have its own metadata and is time-varying. The benefit to using metadata is that metadata is evaluated and stored more efficiently than attribute values.