The Refraction rollout is part of the Generic material's parameters.
Refraction
Dispersion
Legacy Parameters
Example: The Refraction Color Parameter
This example demonstrates the effect of the Refraction color parameter to produce glass materials. The material has a gray Diffuse color, white Reflection color, and the Fresnel option is turned on.
Example: The Fog Color Parameter
This example demonstrates the effect of the Fog color parameter. Notice how the thick areas of the object are darker in the two images on the right because of the light absorption of the fog.
Example: Translucency Mode - SSS
This example demonstrates the effect of the Translucency Mode SSS.
Example: Translucency Mode - Volumetric
This example demonstrates the effect of the Translucency Mode Volumetric.
Example: The Refraction IOR Parameter
This example demonstrates the effect of the Refraction IOR parameter. Note how light bends more as the IOR deviates from 1.0. When the index of refraction (IOR) is 1.0, the render produces a transparent object. Note however, that in the case of transparent objects, it might be better to assign an opacity map to the material, rather than use refraction.
Example: The Refraction Glossiness Parameter
This example demonstrates the effect of the Refraction glossiness parameter. Note how lower Refraction glossiness values blur the refractions and cause the material to appear as frosted glass.
Example: The Refraction Depth Parameter
This example shows the effect of the Refraction depth parameter. Note how too low of a refraction depth produces incorrect results and areas with total internal reflection are also affected by the Reflection depth.
Example: Dispersion
This example demonstrates the Dispersion capabilities of the V-Ray material and the effect of the Abbe parameter.
Example: Thin-Walled
This example shows the effect of the Refraction Thin-Walled option.
Example: Thin-Walled Color
This example shows the effect of the Refraction Thin-Walled color option.
Notes
1 - Calculated in the default SketchUp unit - inches.
2 - When a Bitmap texture is mapped in this slot, its color space is automatically adjusted. Copy-pasting, replacing or wrapping a texture does not trigger this automatic adjustment. It is reserved solely when creating a Bitmap in the specified material slot.