RenderMan product manager, Mark Manca, delivers an introduction to USD and its benefits for the future of filmmaking

Over the past several years, Pixar’s USD has stormed into the collective consciousness of the animation and visual effects industry. But what is USD, exactly? And what does it mean to artists? And beyond that, how will my applications of choice use USD, and how does it work with renderers such as RenderMan?

USD plays a big role at Pixar. Its ability to handle assets at scale can be seen within the antiques mall in Toy Story 4

WHY USD AND WHAT IT DELIVERS:

The first thing to know is that USD is not just a file format. While USD stands for ‘Universal Scene Description’ and does ship with two main file formats, it is the additional features within the technology stack that have caused USD to be so compelling to studios. USD’s secret sauce is in its architecture and implementation. USD enables:

• Collaboration - teams can use USD within modern, overlapping data pipelines

• Non-destructive workflows - opinions, variations and layers allow artists from different areas of the pipeline to work on the same asset at the same time

• Interchange - pass many kinds of data between applications

• Schemas, geometry, materials, lights, volumes, crowd rigs (more coming!)

• Performance - fast reads and writes will keep you working and creative • Renderers such as RenderMan to plug into it - USD-enabled applications can render to the renderer of their choice via a sister technology named Hydra

USD is the culmination of all of Pixar’s years of experience in describing geometry and scenes, in a technology that fosters collaboration between teams within non-destructive workflows. An important cornerstone of the effort is data interchange between applications. And while listed towards the end of the list, performance is not least. Performance is critical to enable artists to interact with large amounts of scene data and to work within the larger context of their worlds. Finally, by providing the ability for multiple rendering backends to plug into Hydra, USD + Hydra offer a highly capable abstraction layer for renderers to render USD no matter where Hydra is used.

PERFORMANCE, COMPLEXITY, COLLABORATION AND CREATIVITY

The complexity of today’s animated and VFX films is several orders of magnitude higher than it was in the days of the original Toy Story in 1995. USD and Hydra have been written to scale to the demands of modern productions.

An example of this is what we call the ‘fractal complexity’ of Toy Story 4. The full environment was modelled and instanced. You can start from a satellite’s eye view of the environment, and then travel down to the level of detail of an individual button contained within the breadth of knickknacks within the antiques mall, one of the larger set pieces within the film.