The vMaterials are a collection of MDL materials designed for physically based rendering, representing real world materials. You can register for a free download here. vMaterials can be rendered with mental ray 3.13 as well as with any Iray plugin, such as NVIDIA® Iray® for Maya.

 

To use the vMaterials for rendering with mental ray for Maya 2016, you have to add the following definition to your Maya.env file (on Windows):

MI_MDL_PATH=C:\ProgramData\NVIDIA Corporation\mdl;C:\Users\<YourUsername>\Documents\mdl;

To find out how to apply the MDL materials in your scene, check our post on Using MDL with mental ray for Maya 2016.

Some materials are dependent on the scene unit and assume meter by default. You can either change the scene scale to meter or you can convert the scene unit dependent parameters. For example, the clarity parameter in the gem materials should be multiplied by 100 if the linear working unit is centimeter.

Note: mental ray 3.13 supports MDL v1.1 and the vMaterials are based on MDL v1.2.  Nevertheless, most materials are compatible and can be rendered with mental ray 3.13 out of the box.

In this post, we introduce the newest features of the mental ray for Maya 2016 plugin that is delivered with Autodesk Maya 2016 and can be downloaded here. Stay tuned for more in-depth posts on the features.

Render Settings Redesign

This version comes with a complete new layout of the Render Settings. Our goal is to make the rendering experience with mental ray straight forward and easy. Settings are greatly simplified and grouped together. Five tabs allow to find settings sorted by topic. For advanced users, each tab provides the ‘Advanced Settings’ mode with more detailed controls to fine-tune the rendering.

The Scene tab contains a simplified render passes system for standard utility passes

as well as MILA Light Path and Matte Pass passes.

A more throrough introduction to the new Render Settings will follow shortly.

NVIDIA Material Definition Language

mental ray 3.13 renders materials defined by the NVIDIA Material Definition Language (MDL). MDL is an NVIDIA initiative to standardize physically based material designs in a common format, see http://www.nvidia.com/MDL. Prepackaged MDL materials can be applied in mental ray for Maya 2016. We will provide you with an introduction on how to use MDL in Maya 2016 and with examples for download in this blog soon.

Light Importance Sampling By Default

Light Importance Sampling is now enabled by default. It gives a significant speed / quality advantage out of the box especially with modern and complex lighting setups, emissive objects, and very many light sources. In addition, new heuristics have been incorporated that automatically determine which light sources in the scene are physically plausible and would benefit from importance sampling. This way, traditional idealized light sources and simple lighting setups can be detected and handled separately, like they may be excluded from importance sampling to retain an overall benefit even though this feature is generally enabled. Custom light shaders are fully supported and will be included in importance sampling if they adhere to physically plausible emission and distribution rules.

Deep OpenEXR

mental ray 3.13 adds support for generating ‘deep’ data and output to OpenEXR files. The resulting image is saved in the DeepTile form of the OpenEXR 2.0 file format, storing additional information of the pixel colors along the Z axis. It is possible to save deep and simple 2D data into different frame buffers during the same rendering.

UV Tiles Optimized

Rendering UV-tiled textures is faster and more memory efficient in this version because it is based on a native mental ray shader. It auto-creates and loads the tile textures into mental ray on demand, making sure that only those tiles that are actually accessed get loaded into memory. The shader is part of a new package called coreutil, which collects essential mental ray utilities and helper functions.

Create Lights menu 

There is a new section in the Create|Lights menu for mental ray lights showing modern mental ray lights in a prominent and easily accessible place.

Object Lights

Using custom geometry to light your scene is now possible with mental ray for Maya 2016. You can assign the new ‘Object Light’ material to your geometry or, with the geometry selected, you can choose ‘Object Light’ from the new mental ray section in the Create|Lights menu. This will turn your geometry into a light.

 

                           Light bulb model courtesy of David Hackett.

Rendering Bifrost with mental ray

Bifröst is a procedural framework that can create simulated effects ranging from liquid to foam, bubbles, spray and mist. These effects can be rendered using the bifrost geometry shader delivered with mental ray for Maya 2016.

Autodesk published videos on bifrost and showing mental ray rendering at the end of each:

Maya 2016: Adaptive Aero Solver in Bifrost
Maya 2016: Guided Simulations in Bifrost
Maya 2016: Adaptive Foam in Bifrost

XGen hair shading and displacement

Rendering XGen with mental ray has been improved and enhanced with new features.

The default XGen hair shader for mental ray is now xgen_hair_physical. It is based on the mental ray human hair shader mib_illum_hair_x which has been improved with mental ray 3.13. It now adds contributions from indirect lighting to the shading. New parameters have been added to tune the tube shading look and to control the internal color noise effect.

Displacing sphere and dart primitives is now possible allowing for a much wider use-case for these primitives.

Texture Filtering based on Ray-Differentials

For advanced ‘elliptical’ texture filtering in Maya’s file node, we are now using ray differentials provided by mental ray core. This introduces more accurate and artifact-free texture filtering even across ray traced reflections and refractions.
To enable it, select a file node, choose ‘Mipmap’ as filtertype, go to the mental ray section and enable ‘Elliptical filtering’. You can choose between ‘Bilinear’ or ‘Bicubic’ filter mode.