Material ID maps are textures that are generated via Knald's baker & contain RGB information based upon the number of imported High Poly mesh parts, with each mesh being assigned a unique color. They are extremely useful for texturing purposes; allowing the user to create selection masks based upon different materials on a mesh.
It is possible to assign a maximum of 255 unique colour values within a Material ID map, either allowing Knald to generate them automatically for you as the number of mesh parts increase or by using the color pickers found next to each High Poly mesh within the Material ID group. Black (0.0) is always used as the background color.
They can be generated via from either of the following sources:
Use Median Anti-aliasing This check box is a toggle between Average & Median anti-aliasing.
Source: The method of generating the Material ID map.
Color Scheme Allows you to choose how Knald assigns colors.