ID Map
Material region mask
Also known as: Material ID · Colour ID map
Definition
An ID map is a baked texture where each material region of a model is filled with a flat solid colour. Substance Painter uses ID maps to auto-mask material assignments: a green pixel becomes leather, blue becomes metal, red becomes fabric. This turns a tedious manual selection step into one click, especially for models with many distinct material zones like character costumes or vehicles.
In production
Author the ID map by assigning vibrant unique colours to polygroups in ZBrush, or by painting flat colours per material region in your DCC — a common convention is pure red for skin, green for cloth, blue for metal, keeping each colour maximally distinct so anti-aliasing at the borders doesn't create an ambiguous intermediate colour that confuses the mask generator. Bake from the high-poly to the low-poly alongside normal and AO in xNormal, Marmoset Toolbag, or Substance Painter's own baker; import into Substance Painter's Color Selection mask generator to instantly isolate each material zone with a single click. The most common ID map mistake is letting two unrelated polygroups share the same or a very similar colour, which causes the mask generator to select both regions at once — vehicle artists with dozens of small material zones are especially prone to this. Marmoset Toolbag's baker can also export a "material ID" pass directly from named material slots rather than polygroups, which is faster for props already built with separate materials in the DCC.
