Map Channels

Use map channels to define textures, adding complexity and realism to materials. For example, you can replicate the bumps in a ceiling tile surface by using a noise texture and applying it to an object representing a ceiling in the scene.

After textures are applied to an appearance and modified to your preference, a texture can be adjusted on the object using various attributes available in the Texture Editor.

Map Channel	Description
Reflectivity Map	Use a reflectivity map to simulate a scene reflected on the surface of a shiny object. For reflectivity maps to render well, the material should be shiny, and the reflection image itself should have a high resolution (at least 512 by 480 pixels).
Transparency Map	You can specify areas of transparency and opacity by using the transparency map channel. The effect of transparency is best previewed against a pattern background.
Cutouts Map	You can select an image file to use for cutouts mapping. Transparent areas are fully transparent. When you use transparency for frosting or translucent effects, reflectivity is maintained. Use a cutout in addition to make the material take a particular shape or pattern. Cutout areas do not reflect.
Self Illumination Map	White areas of the map render as fully self illuminating. Black areas render with no self illumination. Gray areas render as partially self illuminating, depending on the grayscale value. Self illumination means that the glowing area is not affected by lights in the drawing (its ambient color component goes away), and does not receive shadows.
Bump Map	You can select an image file or procedural maps to use for mapping. Bump mapping makes an object appear to have a bumpy or irregular surface. When you render an object with a bump-mapped material, lighter (whiter) areas of the map appear to be raised and darker (blacker) areas appear to be low. If the image is in color, the gray-scale value of each color is used. Bump mapping increases rendering time significantly but adds to the realism. Use bump maps when you want to take the smoothness off a surface, or to create an embossed look. Keep in mind, however, that the depth effect of a bump map is limited because it does not affect the profile of the object and cannot be self-shadowing. If you want extreme depth in a surface, you should use modeling techniques instead. The bumps are a simulation created by perturbing face normals before the object is rendered. Because of this, bumps do not appear on the silhouette of bump-mapped objects. The Bump map slider adjusts the degree of bumpiness. Higher values render as higher relief and negative values inverses the relief.