Using multiple illumination maps using-multiple-illumination-maps
Some applications may require a different illumination map for different kinds of materials.
Up to three illumination maps can be authored for each vignette. The illumination map for a render operation is selected with the illum=
and or gloss=
commands.
Default selection - If illum=
or gloss=
are not specified, the renderer uses the first authored illumination map (typically map A, aka the ‘Flat’ illumination map).
Automatic selection with gloss=
- If illum=
is not specified or is set to -1
, the renderer compares the specified gloss=
value with the gloss values associated with each illumination map in the vignette. It chooses the illumination map whose gloss value is closest to the specified gloss=
.
Explicit selection with illum=
- If illum=
is specified and set to 0
, 1
, or 2
, the renderer uses the corresponding illumination map; gloss=
is ignored for selecting the illumination map.
If the vignette contains only one illumination map, the renderer uses that map and ignore the illum=
and gloss=
commands.