This page provides information about the RGB to HSV node in V-Ray for Cinema 4D.
Overview
The V-Ray RGB To HSV node can be used to convert a color from an RGB color model to an HSV color model.
Note that when converting, the Hue value is in degrees. This results in the Red channel having values up to 360. This is not useful in some cases. For a workaround, see the Workaround example.
General
Workaround Example
This example shows how you can use the hue of a texture to generate UVWs for a Ramp node. Only using the hue means that the actual color values are ignored. In this case, the black squares are not regarded when generating the UVWs for the Ramp.
Notice how the Ramp on top has more nodes connected to it. Firstly, we need to convert the Bitmap's RGB values to HSV values using the RGB to HSV node. After conversion, the Hue values are in degrees. This results in the red channel having values up to 360. Therefore, we pass the result through a Color Channel node. This is done, so that we can normalize the red channel. Inside the Color Channel, we set the Multiplier to 0.003, as that is the result of dividing 1 by 360. We connect the resulting output to a Color to UVW node, which transforms the color values into a UVW map. We then use that texture to map out the Ramp.
