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The following attributes are offered for surface shaders that support reflections:
Max Distance
The maximum distance to search for reflections. Using a value that excludes large portions of the scene that cannot be reflected anyway will improve rendering speed. Using a value of 0 will include all scene objects, regardless of their distance; this is the default.
Samples
Number of samples for the reflection. Higher sample counts produce smoother reflections. The required number of samples to get smooth reflections varies from case to case and depends on the reflected objects and the value of the Blur attribute. In some cases, 2 to 8 samples may suffice. In some other cases, hundreds of samples may be required.
Blur
Angle in radians that defines a sampling cone. Larger values produce smoother reflections but may require a higher number of samples.
Noise Amplitude
Noise Frequency
Amplitude and frequency of noise applied to the reflection.