For the most part, the mental ray renderer treats 3ds Max maps and materials the same way the default scanline renderer does. The exceptions are listed below. In general, if the mental ray renderer does not recognize a map or material, it renders it as opaque black.
The maps used to create reflections or refractions, Flat Mirror, Raytrace, Reflect/Refract, and Thin Wall Refraction, are supported by the mental ray renderer. However, the mental ray renderer simply uses these maps as indications to use its own ray-tracing method, leading to some restrictions on which parameters are supported, as described in the sections “Materials” and “Maps,” below.
When reflections and refractions are ray traced, applying Blur (or Distortion, in Flat Mirror) does not apply to reflections or refractions of environment maps. In general, Blur and Distortion render differently than they do with the default scanline renderer, and you might have to experiment with parameter values to get a comparable rendering result.
The mental ray renderer supports all Raytrace material settings except for the antialiasing parameters and the settings found under Rendering Raytracer Settings and Rendering Raytrace Global Include/Exclude. All these options are specific to the default scanline renderer.
PSD files are supported, but are translated into binary data, and because of this, consume a lot of memory and increase render time. To reduce the time involved, convert the PSD file to a format such as BMP.
The same is true of TIFF files. In addition, there are certain TIFF subformats that the mental ray renderer does not support; specifically, LZW, CCIT (fax), or JPEG compression; non-RGB color models such as CMYK, CIE, or YCbCr; or multiple images in the same file (in this case, only the first image is used). The mental ray renderer does support bilevel (1-bit), grayscale (4- or 8-bit), color map (4- or 8-bits), RGB(A) (8-, 16-, or 32-bit) TIF images, and TIF files with image strips.
This map tells the mental ray renderer to use ray-traced reflections and refractions. Most parameters are supported, but the parameters Blur Offset, First Frame Only, Every Nth Frame, and Atmosphere Ranges are not supported.