Illumination map selector. Specifies the illumination map that this material prefers to be rendered with.
illum=-1|0|1|2
If the specified illumination map is not available in the target vignette, the nearest available map is used instead.
illum=-1
Specifies that the illumination map is selected automatically based on the gloss=
value.
Material attribute. Ignored if the vignette does not define multiple illumination maps.
illum=-1