The mental ray® renderer from mental images® 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 images and mental ray are registered trademarks, and photon map is a trademark of mental images GmbH & Co. KG, Berlin, Germany.
The mental ray renderer in Autodesk VIZ supports the mental ray version 2 (mi2) and version 3 (mi3) formats. It does not support the mental ray version 1 (mi1) format.
Compared to the default Autodesk VIZ 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 Autodesk VIZ 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.
To use the mental ray renderer:
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Choose Rendering menu > Render. The Render Scene dialog displays.
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On the Common panel, open the Assign Renderer rollout, then click the “...” button for the Production renderer.
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On the Choose Renderer dialog, click to select mental ray Renderer, and then click OK.
Tip: After you make the mental ray renderer the active production renderer, you can click Save As Defaults to make the mental ray renderer the default renderer for all new scenes. This can be a convenient way to avoid extra setup time.
Now when you render, the Render Scene dialog appears with 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 a .mi file that you can render later, perhaps on a different system. Controls for choosing whether to render, save to a .mi file, or both, are on the Translator Options rollout.