The USD Notice Framework (UNF) is built over the native Tf Notification System in USD, an open source extensible software platform for collaboratively constructing animated 3D scenes. It provides a C++ and Python API to efficiently manage the flow of notifications emitted when authoring the USD stage.

While USD notices are delivered synchronously and tightly coupled with the sender, UNF introduces standalone notices that can be used for deferred delivery and can be aggregated per notice type, when applicable.

Pixar designed USD as an open and extensible framework for composable data interchange across different tools. As such, it is highly optimized for that purpose. Born out of Pixar's Presto Animation package, some application-level features were intentionally omitted to maintain speed, scalability, and robustness to support its core usage.

When editing USD data, the stage and layers produce a high volume of change notifications that can be hard to manage when crafting a performant user experience. UNF provides a framework to aggregate and even simplify change notifications across a series of edits on a USD stage. It allows developers to build performant and sustainable interactive applications using USD as its native data model.

Full documentation, including installation and setup guides, can be found at https://wdas.github.io/unf