Models, Materials and USD

USD

The fundamental representation for assets in Omniverse is Pixar’s open-source Universal Scene Description (USD). While USD includes a file format, it is much more than that. USD is a powerful scene representation with an API that allows complex property inheritance, instancing, layering, lazy loading and a wide variety of other key features. Omniverse uses USD for interchange through the Nucleus DB service.

Additional and Recommended Source of USD Information

What Makes USD Unique

5 Things To Know About USD

Converting to USD

The Omniverse gives you all the tools you need to quickly and easily convert assets into and out of USD.

Asset Converter

Accessible via Apps on the omniverse, users can convert models into USD using the Asset Converter Service (Extension).

Format

Name

Description

.fbx

Autodesk FBX Interchange File

Common 3D model saved in the Autodesk Filmbox format

.obj

Object File Format

Common 3D Model format

.gltf

GL Transmission Format File

Common 3D Scene Description

Connectors

Specialized connectors offer a more finely tuned conversion process. Through connectors, native files are directly translated to usd.

Note

Because connected applications often have numerous file conversion capabilities, a path to even the most obscure formats may be possible via various connectors.

MDL

NVIDIA has developed a custom schema in USD to represent material assignments and specify material parameters. In Omniverse, these specialized USD’s get an extension change to .MDL signifying that it is represented in NVIDIA’s open-source MDL (Material Definition Language).

MDL Texture Formats Accepted

MDL Materials throughout Omniverse can accept texture files in the following formats.

Extension

Format

Description

.bmp

Bitmap Image File

Common image format developed by Microsoft.

.dds

DirectDraw Surface

Microsoft DirectX format for fextures and environments.

.exr

OpenEXR

High Dynamic Range format developed by Industrial Light and Magic

.gif

Graphical Interchange Format File

Common color constrained lossless web format developed by CompuServe.

.hdr

High Dynamic Range Image File

High Dynamic Range format developed by Industrial Light and Magic.

.jpeg

Joint Photographic Experts Group

Common “lossy” compressed graphic format.

.jpg

Joint Photographic Experts Group

Common “lossy” compressed graphic format.

.png

Portable Network Graphics File

Common “lossless” compressed graphics format.

.psd

Adobe Photoshop Document

The native format for Adobe Photoshop documents.

.tga

Truevision Advanced Raster Graphics Adapter

High Quality raster graphic format developed by Avid Technology |

Custom schemas

NVIDIA has also developed custom USD schemas to represent general physical properties of objects (e.g. mass, moment of inertia), the way they are constrained to move (e.g. pivots, joints) and parameters specific to a particular Physics simulator (e.g. NVIDIA’s open-source PhysX).