Friday, August 12th, 2022 Posted by Jim Thacker

Nvidia fully open-sources MDL

Nvidia is to fully open-source MDL, its cross-platform Material Definition Language, making the MDL Distiller and GLSL backend available open-source as well as the MDL SDK.

The announcement was made at Siggraph 2022.

Ensures real-world materials display consistently across applications
Developed to ensure that physically based materials displayed consistently in different versions of Nvidia’s own renderers, Iray and the now-defunct Mental Ray, MDL has since been adopted in other DCC tools.

MDL is now supported in software including Adobe’s material authoring tools Substance 3D Designer and Substance 3D Painter, Chaos’s V-Ray renderer, and Unreal Engine, and by the Megascans asset library.

It is also the standard material format within Omniverse, Nvidia’s online 3D design collabortion platform.

But wasn’t MDL open-source already?
Nvidia began the process of open-sourcing MDL in 2018, starting with the MDL SDK.

This week’s announcement completes that process, with the remaining key technologies, the MDL Distiller and the GLSL backend, also due to become available open-source.

Newly open-sourced features help to support MDL in real-time renderers
The GLSL backend provides support for OpenGL Shading Language, the principal shading language used by the OpenGL graphics API, and Vulkan, its successor.

Both are widely used in real-time render engines, including the viewport renderers of DCC applications.

ALthough some apps are now shifting away from OpenGL for viewport rendering, Vulkan is gaining ground: it is supported in Adobe’s Substance 3D Stager, and is due to be supported in Blender’s Eevee renderer.

The MDL Distiller also helps developers of less graphically capable renderers to support MDL materials, automatically simplifying MDL materials to reduced material models.

It is intended to avoid artists having to author separate versions of a material: a full version, plus simplified variants for renderers that don’t support all of its features.

Instead, renderer developers provide MDL Distiller rules for how the full material should be converted.

When new features are added to the renderer, the Distiller rules can be updated alongside them, meaning that existing MDL materials support those new features without having to be re-authored.

Licence, system requirements and release date
The source code for the MDL SDK is available under a BSD 3-clause licence. Compiled binaries of the latest release, MDL SDK 2021.1.4, are available for Windows 7+, Linux and macOS.

At the time of writing, the MDL SDK webpage still lists the open-source release of MDL Distiller as coming soon. We’ve contacted Nvidia to ask when the source code will be available, and will update if we hear back.

Updated 23 August 2022: Nvidia told us that the GLSL backend will be available in MDL SDK 2022, the next release of the SDK, due imminently.

The MDL Distiller will be open-sourced “later this year”. The source code will also be available on GitHub, with Nvidia currently planning to have it in the same repository as the rest of the SDK.

Read Nvidia’s announcement that MDL SDK is being made fully open-source