USD simplifies 3D data exchange within digital content workflows; includes Hydra previewer.

Pixar Animation Studios has released its Universal Scene Description (USD) technology, used for the interchange of 3D graphics data through various digital content creation (DCC) tools, as open source. USD is a proven effective and scalable data exchange solution for the complex workflows of CG film and game industry studios.

With the initial release today, Pixar is opening up its development process and providing code used internally at the studio. “USD synthesizes years of engineering aimed at integrating collaborative production workflows that demand a constantly growing number of software packages,” says Guido Quaroni, Vice President of Software Research and Development at Pixar.

Pipelines capable of producing computer graphics films and games typically generate, store, and transmit great quantities of 3D data, which we call “scene description”.  Each of many cooperating applications in the pipeline  (modeling, shading, animation, lighting, fx, rendering) typically has its own special form of scene description tailored to the specific needs and workflows of the application, and neither readable nor editable by any other application.   Universal Scene Description (USD) is the first publicly available software that addresses the need to robustly and scalably interchange and augment arbitrary 3D scenes that may be composed from many elemental assets.  

USD provides for interchange of elemental assets (e.g. models) or animations.  Unlike other interchange packages, USD also enables assembly and organization of any number of assets into virtual sets, scenes, and shots, transmits them from application to application, and non-destructively edits them (as overrides), with a single, consistent API, in a single scene graph. USD provides a toolset for reading, writing, editing, and rapidly previewing 3D geometry and shading.  In addition, because USD’s core scene graph and “composition engine” are agnostic of 3D, Pixar says USD can be extended in a maintainable way to encode and compose data in other domains.

Cooperating on the details

USD is an OpenSource project released under a modified Apache license. It provides a toolset for reading, writing, editing, and previewing 3D scene data. Many of its features are geared to performance and large-scale collaboration. The open source release includes Hydra, a high-performance preview renderer capable of interactively displaying large data sets.

“With USD, Hydra, and OpenSubdiv, we’re sharing core technologies that can be used in filmmaking tools across the industry,” says George ElKoura, Supervising Lead Software Engineer at Pixar. “Our focus in developing these libraries is to provide high-quality, high-performance software that can be used reliably under demanding production scenarios.”

After Industrial Light and Magic joined the Disney family, ILM began using Hydra and USD. “Integrating Hydra into our proprietary Virtual Production Renderer helped us solve one of our biggest challenges,” says Kevin Wooley, Virtual Production Engineering Lead at ILM. “With the performance improvement, we can handle incredibly complicated digital environments, with thousands of pieces of geometry, while preserving the editability of the scene.”

Along with USD and Hydra, the distribution ships with USD plugins for some common DCCs, such as Autodesk’s Maya and The Foundry’s Katana.