V-Ray for Rhino Manual - Rum

Forth example is to use gradient color in refractive material. Same as previous examples, use a
gradient grayscale Bitmap as the Diffuse Transparency mask. Add a Refraction layer to create the
half transparent and half opaque effect.
Fifth Example is the same as the Third one, only difference is adding a Refraction layer, and
changes Transparency color of Diffuse2 to white. This will make the white area at the middle
become transparent. Rendered image as on the right
The example above can not have the transparent quality at the top and bottom of the cup because
of the black color in the grayscale gradient Bitmap. The last example here is to use a pre-made
gradient Bitmap as the Refraction Transparency map. Set the Diffuse Transparency to a usual white,
and then assign the Bitmap to Refraction under Refraction control panel, you will get the same
result as the image shown on the right.
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