A multiplier is a DDS image that controls the level of shading on your creation. Starting at the neutral mid grey shade (RGB 128, 128, 128), anything darker will add shade, and anything lighter will cause lightness (not the same as environmental highlights of the specular; see also: What is a specular?).
Multipliers can be drawn by hand or “baked” (a process where a 3D program makes the multiplier for you based on your UV map – something many creators now do – see: What is baking?).
Multipliers can also make parts of your mesh transparent when used with an alpha (as demonstrated in What is an alpha?).
Although no image has greater importance than another, creators usually make their multiplier first and use this as a basis for the other textures and for refining the mesh’s UV mapping. The specular, RGB Mask and overlay images are easily made once the multiplier is complete.
The size of your multiplier (and therefore your UV map) is determined by:
- How much space the creation will occupy in the game compared to a 256 x 256 pixel floor tile
- How much additional detail needs to be added
- The dimensions are typically 128, 256, 512 or 1024 (maximum) pixels in height or width
The image below is divided into quarter-tile segments. The cushion of the EA chair (in top down view) would occupy no more than quarter of a tile, so it’s mapped to approximately one quarter of the floor tile space (that is: 128 x 128 pixels). And you can see that other parts have been mapped in the same way.
To learn more about what is a multiplier and how you can use it, please see Object Creation Part 2: Object Textures.