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Affect Alpha – When enabled, makes shadows affect the alpha contribution of the matte surface. Areas in perfect shadow will produce white alpha, while completely unoccluded areas will produce black alpha. Note that GI shadows (from skylight) are also computed, however GI shadows on matte objects are not supported by the photon map and the light map cache GI enginesengine, when used as a primary enginesengine. You can safely use those that with matte surfaces as secondary engines.

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Trace Depth – Specifies the number of times a ray can be reflected. Scenes with lots of reflective and refractive surfaces may require higher values to look correct. A value of -1 specifies this option is controlled by the global Render Settings.

Notes

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