This page provides information on the MDL Material.


Overview

The VRayMDLMtl material loads NVIDIA Material Definition Language files (.mdl) and renders them directly with V-Ray.

V-Ray supports NVIDIA Material Definition Language, version 1.7.2.

The MDL Material does not work within Distributed Rendering at this time.

The MDL Material is currently not supported by V-Ray for Maya 2024, running on macOS.



||Right-click on the geometry|| > Assign New Material... > VRay section > VRay Mtl MDL



||V-Ray Shelf|| > Right-click to Create V-Ray Materials button > VRay Mtl MDL



||Hypershade|| > Window tab > Create... > VRay section > VRay Mtl MDL





Installed Material Library

The following MDL material files are included when installing V-Ray for Maya. They are located in Local Disk (C:) > Program Files > Chaos > V-Ray > Maya 20xx for x64 > vray > mdl.




Aluminum Anodized



Architectural



Asphalt





Carbon composite



Carpet Berber White



Ceramic Tiles Small




 
Chrome


 
Coated Flipflop Paint


 
Coated Flint Glass




 
Colored Wax


 
Concrete


 
Concrete Polished




 
Copper


 
Granite Black


 
Mahogany Floorboards




 
Marble White


 
Metal Examples


 
Noise Flow Glossy




 
Noise Perlin Glossy


 
Noise Worley Glossy


 
Pattern Blended




 
Pattern Checker Glossy


 
Porcelain


 
Resin Polyurethane Matte




 
Rubber Studded Black


 
Stucco


 
Walnut Semi-Gloss





Basic

The Basic rollout provides the attributes used to set the path to the .mdl file that you wish to load into your chosen material, and an Update button needed to refresh the other attributes available, based on the material file used.


MDL file – Specifies the file path and .mdl file loaded.

Chosen material – If more than one material definition is included in the loaded .mdl file, the selected materials will be seen in the rollouts below.

MDL parameters– The Update button refreshes the additional material-specific attributes for the loaded .mdl file.



Parameters

Any additional material-specific attributes (if any) are listed in this rollout. The example below shows parameters for the Coated Flip-flop Paint material.


 MDL material attributes that can accept Render Nodes to map color values can now use File textures as input. Note that while other texture types may also be used, only File textures are guaranteed to work properly.


Asphalt parameters

Advanced

Max Ray Depth – Specifies the maximum reflection/refraction depth for the shader.

Remap Roughness – When enabled (default), determines whether the plugin expects squared values for GGX Roughness settings.



System Attributes

Filename – Specifies the file path and .mdl file loaded.



Importing NVIDIA vMaterials

In order for the MDL Material to correctly import NVIDIA vMaterials, the following two paths should be set in the environment variable shown below:

VRAY_MDL_PATH_MAYA20yy_x64=%PROGRAMFILES%\Chaos\V-Ray\Maya 20xx for x64\mdl;%PROGRAMDATA%\NVIDIA Corporation\mdl;%USERPROFILE%\Documents\mdl

where xx is the version of Maya installed.


Example:

VRAY_MDL_PATH_MAYA2024_x64=C:\Program Files\Chaos\V-Ray\Maya 2024 for x64\mdl;%PROGRAMDATA%\NVIDIA Corporation\mdl;%USERPROFILE%\Documents\mdl


Importing MDL Files from Substance Designer

In some cases, when using MDL files exported from Substance Designer, V-Ray may fail to load some modules. In order to load these modules, a folder needs to be set up before starting Maya, as explained below:

1.  Make a folder, for example, X:\MDL, that will act as the MDL repository. Put the MDL modules that are exported from Substance Designer into this folder.

2.  Put the textures needed by the MDL materials in the same repository in their respective subfolder (for example, X:\MDL\MDL_Plywood_02).

3.  Tell V-Ray where the MDL repository is by appending it to the VRAY_MDL_PATH_MAYA20xx_x64 environment variable.

4.  Find the folder where Substance Designer keeps its MDL modules (usually C:\Program Files\Adobe\Adobe Substance 3D Designer\resources\view3d\iray\alg but may differ from version to version) and append its path to the same environment variable. 

In the end, the environment variable should look something like:

VRAY_MDL_PATH_MAYA2018_x64=C:\Program Files\Chaos\V-Ray\Maya 2018 for x64\mdl;C:\Program Files\Adobe\Adobe Substance 3D Designer\resources\view3d\iray\alg;X:\MDL


Known Limitations

  • material_emission.mode is ignored
  • material.backface is ignored

  • df::diffuse_transmission_bsdf is not supported

  • df::backscattering_glossy_reflection_bsdf is not supported

  • df::measured_bsdf is not supported

  • From the “alternative distribution functions”, only df::microfacet_ggx_smith_bsdf is implemented

  • df::measured_edf and df::spot_edf are not supported

  • df::anisotropic_vdf is not supported

  • 3D textures are not yet supported

  • The multiscatter_tint parameter in simple_glossy_bsdf, microfacet_ggx_smith_bsdf, ward_geisler_moroder_bsdf is ignored.
  • The tint (color reflection_tint, color transmission_tint, bsdf base) modifier overload for separate tinting of the reflective and transmissive light paths is not supported.

References