Shading Group attributes

In the Shading Group’s Attribute Editor, the mental ray section contains the following options:

Flags

These are the options in the Flags section.

Opaque: Turn this on if the material is fully opaque. It should assist in speeding up mental ray rendering.
Transparency Threshold: Tweak this transparency threshold so that all surface points that are less opaque than specified by this attribute will be considered non-existent. For example, a value of 0.05 removes all surface points with a transparency of 99.5% or more.This allows your object to appear cut out from the texture. An example is to map an image of a tree to a flat plane and use opacity to cut away the parts of the tree that are not there.

Contours

These are the options in the Contours section. Each shading group can have individual contour rendering attributes defined. Set the following options to achieve the desired look. See also Contours.

Enable Contour Rendering: Enables contour rendering for all objects associated with the shading group.
Color: The color of the contour lines. This attribute can only be a color and cannot have a procedural or texture map connected to it.
Alpha: The alpha of the contour lines.
Width: The width of the contour lines.
Relative Width: If off, Width is specified as (fractional) number of pixels. If on, Width is specified in percents of the horizontal image resolution thus maintaining the relative contour size if the resolution changes.
Absolute Width: If on, Absolute Width is specified in percents of the horizontal image resolution set by the user.

Custom Shaders

These are the options in the Custom Shaders section.

Suppress all Maya Shaders: Use this for backwards compatibility as it disables automatic translation of Maya shaders. Only the mental ray ports are evaluated and exported.
Export with Shading Engine/Export with Volume Sampler: When turned on, these both insert additional helper shaders into the export stream. These shaders are required if you want to write custom shaders that cooperate with the Maya base shader package delivered with mental ray for Maya. These options are for advanced mental ray for Maya users only.

Note

The Export with Shading Engine attribute is available for backward compatibility. It should not be used for tuning and should be disabled in most cases.

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