Find this section in the selected object’s shape node. Expand the mental ray section of the shape node’s Attribute Editor to see these options.
The following options are on by default: Visible In Transparency, Transmit Transparency, Trace Reflection, Transmit Refraction, Final Gather Cast, and Final Gather Receive.
In most cases, you want to leave these options on. For example, you want transparency and refraction rays to be transmitted through your object, or you want reflection rays to reflect through your scene several times.
In some cases, however, you may want to customize your scene by switching off one or more of these options. Refer to the descriptions below for the effects that can be obtained by unchecking each of these attributes.
Uncheck this option so that object does not receive any final gather light.
Select your render proxy .mi file to render your render proxy instead of your base geometry placeholder.
For each instance of your base geometry, you can make the selection between rendering the base geometry or replacing it with the render proxy. Use the per-instance Renderable flag. See Renderable for more information.
Use the Min Sample Level and Max Sample Level attributes to set the range of samples used for the selected object. Note that the min and max sample level values set for each object are bound by the global min and max sample level values. See Anti-Aliasing Quality for more information regarding the global sample level values.
This is the object specific minimum number of samples per pixel used when processing an image. This value is clamped to the global min sample level value. For example, if the object specific min sample level is set to -1 and the global min sample level is set to 1, then the global setting of 1 will be used. Based on the Anti-aliasing Contrast (adaptive) settings, mental ray for Maya will increase these samples as needed.
This is the object specific maximum number of samples per pixel used when processing an image. This value is clamped to the global max sample level value. For example, if the object specific max sample level is set to 3 and the global max sample level is set to 2, then the global setting of 2 will be used.
This attribute controls the rasterizer’s shading samples on a per-object basis. See Rasterizer Quality for more information.
Controls how many rays are shot in each final gathering step to compute the indirect illumination. The default is 1000 per sample point, but this tends to be high for test renders (renders can take hours). Test rendering at lower values, usually 100 or 200, is sufficient; higher values are required for final renders. Increasing the value reduces noise but also increases the rendering time.
Max Radius and Min Radius control the size of the sampling region within which Final Gather rays search for irradiance information from other surfaces.
With the default values, Maya calculates values that seem appropriate based on scene dimensions to speed up the render, but this calculation doesn’t allow for complex geometry. Generally, enter a value that is 10% of scene’s overall dimension for the Max Radius, then enter 0.0 for Min Radius. Make further adjustments based on scene geometry detail, how the geometry is arranged in the scene, and how the render looks. For example, use smaller radii to achieve better detailing in nooks and crannies in your scene.
Use this to control how Final Gather uses a speckle elimination filter to prevent samples with extreme brightness from skewing the overall energy stored in a Final Gather sampling region.
Neighboring samples are filtered so that extreme values are discarded in the filter size. By default, the filter size is 1. Setting this to 0 disables speckle elimination, which can add speckles but will better converge towards the correct total image brightness for extremely low accuracy settings. Size values greater than 1 eliminate more speckles and soften sample contrasts. Sizes greater than 4 or so are not normally useful.
Controls the maximum distance at which mental ray for Maya considers photons for global illumination. When left at 0 (the default), mental ray for Maya calculates an appropriate amount of radius, based on the bounding box size of the scene. If the result is too noisy, increasing this value (to 1 to start, then by small increments up to 2) decreases noise but gives a more blurry result. To reduce the blur, you must increase the number of global illumination photons (Global illumination Accuracy) emitted by the light source.
Controls the maximum distance at which mental ray for Maya considers photons for caustics. When left at 0 (the default), mental ray for Maya calculates an appropriate amount of radius, based on the bounding box size of the scene. If the result is too noisy, increasing this value (to 1 to start, then by small increments up to 2) decreases noise but gives a more blurry result. To reduce the blur, you must increase the number of caustic photons (Caustic Accuracy) emitted by the light source.
Specifies the maximum displacement applied to object control points in a normal direction. This provides control over the otherwise automated displacement range to better focus tessellation where most needed. Set this value if you have any displaced objects in your scene. See Max Displace for more information.
