3D Asset Interoperability Using USD and glTF Working Group – 2023 Year in Review

Dec 20, 2023

We’re thrilled to report on a tremendously productive first year for the 3D Asset Interoperability Working Group. Our engaged members have made meaningful progress in aligning key graphics standards like USD and glTF, advancing seamless 3D workflows.

Work Group Bi-weekly Meetings

Since our charter was approved in February 2023, our group hosted 18 well-attended meetings where we educated ourselves on topics ranging from material representations to physics to animation pipelines, and we learned about other formats and open source initiatives. We also coordinated an acclaimed speaker series featuring leaders in areas like game engines, digital content creation tools, and immersive 3D platforms. Videos from these insightful sessions are available here.

PBR Materials

We supported exploring alignment between physically-based rendering approaches, including Pixar’s USD, the Khronos glTF PBR specification, along with partners such as Autodesk and Adobe with OpenPBR, and the ASWF’s MaterialX open source project. Helping to build growing consensus on PBR interoperability will help avoid needless duplication and redundancies in how material properties are authored and preserved across USD and glTF workflows and in industry-leading applications.

Physics

In another key milestone, we brought together physics experts from multiple platforms and engines to outline a common representation for simulation behavior and dynamics between these formats. We are hopeful that a consensus to align the physics extension to USD and glTF is near.

USD – glTF Roundtripping

We established critical groundwork to enable USD and glTF asset conversion with the support of the Khronos Group. We are working towards creating assets and infrastructure to help identify gaps and issues with using glTF and USD together in authoring and deployment pipelines.

Interactivity

The group reviewed the proposed glTF extension for interactivity and behavior graphs from Khronos, and we will continue to work towards industry alignment and interoperability.

Animation and FBX

Recently, we kicked off activities around animation, reviewing Pixar’s proposal for a representation of animation curves. Acknowledging that FBX remains a popular solution for representing and transporting animation structures, the workgroup plans to conduct a gap analysis between FBX and USD/glTF to explore how we can integrate these capabilities.

New Geometric Representations

We hosted a presentation from Pixar on their representation of subdivision surfaces which triggered interest from the glTF team to look into adding this functionality to the glTF specifications. In 2024, we plan on exploring NERFs and Gaussian Splats and gauge interest and feasibility in these new representations.

SIGGRAPH 2023

The Metaverse Standards Forum led two prominent Birds of a Feather (BOF) sessions at the SIGGRAPH Conference in Los Angeles in August 2023:

  • “The Road to the Open Metaverse” session focused on the vision and requirements for an open metaverse. It featured industry leaders like Marc Petit (Epic Games), Yu Yuan (IEEE), Neil Trevett (Khronos Group), Guy Martin (NVIDIA), and others.
  • “State of 3D Asset Interoperability” session highlighted 3D asset interoperability using USD and glTF standards. Experts like Patrick Cozzi (Cesium), Guido Quaroni (Adobe), Henrik Edstrom (Autodesk), and others led the session.

Both sessions were hugely popular, with packed rooms and long lines of eager participants. This tremendous interest underscored the demand for open metaverse interoperability and robust real-time 3D foundations.

A key moment this year at SIGGRAPH was when Pixar, Adobe, Apple, Autodesk, and Nvidia formed the Alliance for OpenUSD to advance USD (Universal Scene Description) as an open standard for 3D graphics and immersive media workflows. We believe the warm welcome for AOUSD into the community of standards organizations was enhanced due to the mutual awareness and understanding between the glTF and USD communities built throughout the year at the Metaverse Standards Forum. We eagerly look forward to working closely and collaboratively with Forum members, AOUSD, Khronos, and open source foundations like ASWF to accelerate the path to interoperable 3D content. More details on the recent liaison announced between Khronos and AOUSD — and the complementary role that the Forum continues to play in ongoing industry coordination is here.

Get Involved!

With the continued passion and combined expertise of our participants, we’re confident that significant strides in streamlining immersive 3D content creation and deployment are on the horizon for 2024. Our working group in the Metaverse Standards provides the ideal forum to transform lofty interoperability goals into tangible realities. We can’t wait to take this mission to the next level together over the next twelve months! Come join us!

– The 3D Asset Interoperability using USD and glTF Working Group