Basic Game Art Concepts - Game Character Creation with Blender and Unity - page 19

Alpha Maps Alpha maps (Figure 1.21) are incredibly useful textures that allow 3D artists
to create organic shapes from simple planes by affecting the planes' transparency. In this
way, artists can create things like leaves, foliage, chain link fences, dirty windows, and
many others with simple geometry. They are also useful for creating particle effects—
fountains of plane objects that can imitate smoke, fire, magic, and other special effects.
These are often displayed in grayscale, with white areas remaining visible, black areas
becoming clear, and everything in between becoming translucent.

Figure 1.21
Alpha map

Specularity Maps These textures control the specularity, or shininess, of a model's sur-
face. These appear as images having color values ranging from white to black, with white
being the shiniest parts and clear being matte-finished areas (Figure 1.22). These are use-
ful in creating the look of worn metal or other materials with varied levels of shininess on
their surfaces.

Figure 1.22
The same image
used as an alpha
map is applied here
as a specularity
map. Note how the
shinier areas are
those mapped as
white in the texture.