V-Ray for Rhino Manual - Rum

When working with complex images it may be necessary to do more than just adjust the Min and Max Rate.
Subdivisions are the next means of quality control with Irradiance Map. Higher subdivisions will yeild
better quality. With Higher subdivisions it may also be necessary to add more samples. In the examples
below both images have been calculated with the same Min/Max Rate, yet the Subdivisions have been
increased from 50 to 100, and the samples have been increased from 20 to 40. You can see in the
arangement of the irrandiance points (the little white dots) that the second image is much smoother.
When Min Rate and Max Rate are too low, “leaking light” happens even if the objects are joined together.
See image on the left for example. This is due to lack of Samples when calculating the Prepass. Of course,
this only happens when using Irradiance Map rendering engine.
Image on the left is rendered with Min Rate and Max Rate of -4 and -3. You can see light comes through the
corner clearly. The image on the right increased the value to -3 and 0 and you can see a big improvement.
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