G = Color: Insert a check in the G = Color checkbox in the Solid Modeling Options window if you are creating a solid model in which the node values represent color. These color numbers used the WDC (Windows Decimal Color) scheme. WDC colors range from zero (black) to 16,777,216 (white). If you're running one of the Colors menu options (Model, Section, etc.), this setting will be activated for you automatically.
Basically, this setting tells RockWorks to assign the voxels the actual color values rather than applying a gradational color scheme. (See Color Models.)