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Subsections

5.1 Upgrading from mental ray 1.9 to 2.x

With mental ray 2.x a new generation of mental ray has become available. Its internal design greatly differs from mental ray 1.9; it incorporates many new features like networking based on a global shared database, incremental changes support, Phenomena, new rendering techniques for caustics and contour rendering, an improved approach to parallelization, and enhanced extensibility. At the same time, obsolete features such as nonrecursive sampling have been removed.

For the mental ray 1.9 user, this means that the transition from mental ray 1.9 to 2.x requires some attention. mental ray 2.x has been designed for maximum compatibility with mental ray 1.9, so in general no additional work will be required by the user to render existing scenes that do not use contour rendering or custom shaders. However, the mental ray installation procedure is slightly different, and shader writers need to make adjustments to the shader sources. This chapter summarizes all changes required when switching from version 1.9 to 2.x.

mental ray 2.x also introduces a number of new features. Some of them improve on 1.9 features and are recommended for future shader designs; these are also listed in this chapter. However, this is not a complete list of improvements in mental ray 2.x.

5.1.1 Rendering Algorithms

If incompatible options are given to mental ray, some of them are overridden to return to a consistent state. In mental ray 1.9.9.20 and higher, including mental ray 2.x, the strategy was changed: instead of re-enabling ray tracing if any other feature such as lenses are used and ray tracing was explicitly turned off, the newer versions do not turn ray tracing back on but change the operation of the feature normally requiring ray tracing. The following features are affected:

5.1.2 Scene Description Language

mental ray 2.x supports a new generation of the mental images scene description language, called .mi2. The language version supported by mental ray 1.9, called .mi1, is still available for backwards compatibility. New translator designs should always use .mi2 because only .mi2 supports instancing, inheritance, incremental changes, and many other features. Here are some rules for using .mi2:

5.1.3 Shader Writing


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Next: 5.2 Upgrading from mental Up: 5. Upgrading Previous: 5. Upgrading
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