9.5.2

938 • CHAPTER 18
THE SHADERS • 939
Contrast
Provides contrast for the result of the diffuse sample color. Zero causes no effect, 0.0% - 100% causes
standard contrast, above 100% causes a wrap contrast (the values that go above 100% wrap around
to 0% again, used to create the Candy materials), negative values provide an inverse contrast that
simulates materials that seem luminescent, such as silver. Appropriate values are -500% to 500%.
Volume Color (Banji only)
This denes the Volume color for the object. Thus you can set the Diffuse Color and Volume Color
separately.
Volume Illumination (Banji only)
Scales the Surface Color to produce attenuation in the illumination of the surface (this simply means it
makes the color darker when the value is close to zero and brighter when the value is closer to 100%
or above). If you are using the Oren Nayar illumination algorithm, you may want to bump up the
illumination by about 10% to 20% because it renders darker usually. Appropriate values are between
0% and 200%.
Shadow Opacity (Banji only)
This parameter is used to scale the shadow opacity. Keep in mind that this changes the shadow opacity
for every surface intercepted by the ray, meaning that going through the surface twice causes the
shadow to be twice as dark.
Specular pages
The three specular highlights controlled in the Specular channels are added to the surface color. All
three Specular channels share the same parameter set, which is described below.
Color
Sets the base specular color for the specular component.