Wednesday, July 27th, 2016 Posted by Jim Thacker

Pixar open-sources its Universal Scene Description


Originally posted on 11 August 2015. Scroll down for details of the official release.

Pixar has announced that it intends to make its Universal Scene Description software available open source.

First presented at Siggraph 2013, USD provides a standard format for exchanging complex VFX scene data – a kind of ‘super-Alembic’, effectively – plus embeddable visualisation via Pixar’s Hydra renderer.

A scalable, collaborative system for exchanging VFX scene data
Whereas Alembic enables studios or off-the-shelf software to exchange cached geometry in a standard format, USD goes further, being geared towards describing the structure of entire scenes rather than individual assets.

The system supports scene-composition features like layering, file-referencing, geometry and shading variants for individual assets, and inheritance.

Pixar describes USD as the marriage of the ‘composition engine’ from Presto, its animation software, to “lazy-access cached scene description”, with enhancements for scalability and modern multi-core systems.

Another core concept is the ability for multiple artists to work simultaneously on the same collections of assets, using separate ‘layers’ of data that are then composited together.

The work is intended to be generalisable to any DCC application – Pixar has been collaborating with tools vendors including The Foundry and Fabric Software – and will come with plugins for “key VFX DCCs”.

The USD distribution will also include embeddable direct 3D visualization via Hydra, Pixar’s GPU renderer.

Already production-proven
Pixar has been using USD in production on Finding Dory for nearly a year, along with accompanying CG short Piper, and the system is also being trialled at major VFX facilities including MPC and Double Negative.

“USD … deserves to become an industry standard similar to OpenEXR and OpenSubdiv,” said The Foundry’s Andy Lomas. “It is exactly what is needed to enable a scalable collaborative pipeline.”

Updated 21 January 2016: Pixar has released a preview build of USD. The compiled binary is for Linux only (CentOS 6.5), and you’ll need drivers that support OpenGL 4.3 or better.

The download can be found on the project website via the link below.

Updated 27 July 2016: Pixar has officially released USD. According to the studio, “MPC, Double Negative, ILM and Animal Logic were among those who provided valuable feedback in preparation for this release”.

ILM has now integrated Hydra into its own in-house Virtual Production Renderer.

The final release of USD includes plugins for Maya and Katana, plus a separate plugin for importing/exporting Alembic files.

Read more about Pixar’s Universal Scene Description system on the project website