2012

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
Self illumination maps make portions of an object appear to glow.
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
A bump map simulates a bumpy or irregular surface.
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.
Understand Map Types
You can select texture or procedural maps within each map channel
(Reflectivity, Transparency, Cutouts, Self Illumination, and Bump) to increase
the complexity of a material.
2224 | Chapter 45 Materials and Textures