Specular maps use a 16-bit grayscale image as a light-management layer in 3D rendering. This light management layer alters the reflectivity of a given surface or texture on an object when rendered. When used with a tint, specular maps mimic the surface color and reflectivity of the rendered object. Maya triggers some confusion in new users, because the Specular Shading tool has five fields where you can load a file, each of which does something slightly different, and none of which are labeled "Specular Map."
- Generate grayscale versions of your texture files. The grayscale image will need to be fairly dark; the darker areas will be less reflective in the final rendered object.
- Save this file in Photoshop or Targa format in the same directory as your working texture files. Maya can import and use Photoshop files natively. Give it a name that indicates it's a specular map.
- Launch Maya with your current work project.
- Select the objects in the main work area that need a specular map applied to them.
- Click on the icon next to "Specular Shading" in the expanding tool panel. You may need to scroll down to spot it. It will have five attributes: "Eccentricity," "Specular Roll Off," "Specular Color," "Reflectivity" and "Reflected Color."
- Select "Specular Roll Off" and click the icon on the right. The file navigation pane will open up; by default it will be in the same directory as any textures loaded into the current project.
- Select the file you saved in Step 2, then click "OK."
- Adjust the lighting on the project to see how the specular map is applied. You can edit the file in Photoshop to adjust the contrasts between the dark and light areas of the map file.