mental ray Renderer

The mental ray ^® renderer from NVIDIA ^® is a general-purpose renderer that can generate physically correct simulations of lighting effects, including ray-traced reflections and refractions, caustics, and global illumination.

Note: mental ray and NVIDIA are registered trademarks, and photon map is a trademark of NVIDIA Corporation.

Scene rendered with the scanline renderer

Same scene rendered with the mental ray renderer

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The second rendering, done with the mental ray renderer, shows caustics cast by refraction through the martini glass. Caustics are also visible in the reflection on the cocktail shaker.

Note: For a discussion of using the mental ray renderer, especially with architectural models, see this white paper.

The mental ray renderer in 3ds Max supports the mental ray version 2 (mi2) and version 3 (mi3) formats. It does not support the mental ray version 1 (mi1) format.

Differences Between the mental ray Renderer and the Default Scanline Renderer

Compared to the default 3ds Max scanline renderer, the mental ray renderer relieves you of the need to simulate complex lighting effects "by hand" or by generating a radiosity solution. The mental ray renderer is optimized to use multiple processors and to take advantage of incremental changes for efficient rendering of animations.

Unlike the default 3ds Max renderer, which renders scanlines from the top of the image downward, the mental ray renderer renders rectangular blocks called buckets. The order in which the buckets are rendered can vary, depending on the method you choose. By default, mental ray uses the Hilbert method, which picks the next bucket to render based on the cost of switching to the next one. Because objects can be discarded from the memory to render other objects, it’s important to avoid having to reload the same object multiple times. This is especially important when you have enabled placeholder objects (see the Processing panel Translator Options rollout).

If you use distributed rendering to render a scene, it might be hard to understand the logic behind the rendering order. In this case, the order has been optimized to avoid sending lots of data over the network. Each CPU is assigned a bucket as the bucket becomes available, so different buckets can appear in the rendered image at different times. See the Renderer panel Sampling Quality rollout.

Note: The mental ray renderer can also be run in a standalone fashion, using a command-line interface based on the mi2 or mi3 scene description format. This is described in the manual mental ray Programming, which is written for programmers writing custom shaders.

Procedures

To use the mental ray renderer:

1. Choose Rendering menu Render Setup. The Render Setup dialog opens.
2. On the Common panel, open the Assign Renderer rollout, and then click the “...” button for the Production renderer.

   The Choose Renderer dialog opens.

3. On the Choose Renderer dialog, highlight mental ray Renderer and then click OK.
   Tip: After you make the mental ray renderer the active production renderer, you can make the mental ray renderer the default renderer for all new scenes by clicking Save As Defaults. This is a convenient way to avoid extra setup time.

Now the Render Setup dialog contains the mental ray controls. You can choose to render the scene with the built-in mental ray renderer, or simply to translate the scene and save it in an MI file that you can render later, perhaps on a different system. Controls for choosing whether to render, save to an MI file, or both, are on the Translator Options rollout.