Transparency: There are two heavy uses for this type of channel.
These channels are incredibly powerful, but require a new way of thinking.
Transparency maps can act sort of like a cape of invisibility; or even better, a cape of semi-invisibility.
A transparency map can turn an orange into a crystal ball, or change a baseball into a wicker ball.
Refraction refers to the way light is bent as it passes through objects.
Different objects in nature use different refractive qualities; the refraction as light passes through water is different than as it passes through glass.
Most 3D applications allow you to determine if and how much refractive qualities are to be assigned to a certain texture.
Texture maps can be semitransparent in the sense of simply letting light pass through them.
Besides the refractive ideas of transparency maps, there are tremendous faux modeling capabilities in transparency channels and mapping.
Sometimes programs separate these ideas of turning a solid object in to one with certain sections being completely see through, into other channels called gen-locking or alpha maps.
The idea of creating a map to essentially designate new geometry is incredibly powerful, but more on that later.
The reflection channel allows an object to reflect other objects or environments around it.
Reflection maps allow you to define which parts of an object will be reflective, and which areas will be matte.
For instance, in Figure 5.
26, the ball on the left has reflection enabled, but no map.
The second ball has a reflection map that causes the blemishes to be non-reflective.
One warning about reflection, though: It increases the time needed to render fairly dramatically, and so should be used only when needed (besides the fact that the world at large is tired of seeing reflective chrome balls on checkered floors; but that is a whole other soapbox).
These channels are incredibly powerful, but require a new way of thinking.
Transparency maps can act sort of like a cape of invisibility; or even better, a cape of semi-invisibility.
A transparency map can turn an orange into a crystal ball, or change a baseball into a wicker ball.
Refraction refers to the way light is bent as it passes through objects.
Different objects in nature use different refractive qualities; the refraction as light passes through water is different than as it passes through glass.
Most 3D applications allow you to determine if and how much refractive qualities are to be assigned to a certain texture.
Texture maps can be semitransparent in the sense of simply letting light pass through them.
Besides the refractive ideas of transparency maps, there are tremendous faux modeling capabilities in transparency channels and mapping.
Sometimes programs separate these ideas of turning a solid object in to one with certain sections being completely see through, into other channels called gen-locking or alpha maps.
The idea of creating a map to essentially designate new geometry is incredibly powerful, but more on that later.
The reflection channel allows an object to reflect other objects or environments around it.
Reflection maps allow you to define which parts of an object will be reflective, and which areas will be matte.
For instance, in Figure 5.
26, the ball on the left has reflection enabled, but no map.
The second ball has a reflection map that causes the blemishes to be non-reflective.
One warning about reflection, though: It increases the time needed to render fairly dramatically, and so should be used only when needed (besides the fact that the world at large is tired of seeing reflective chrome balls on checkered floors; but that is a whole other soapbox).