Graphics Programs Reference
In-Depth Information
of a Ramp shader. In addition, a special curve ramp is attached to the Specular Roll Off
to allow for more precise control over how the specular highlight diminishes over the
surface.
Shader Attributes
Shaders are composed of nodes just like other Maya objects. Within these nodes, attri-
butes define what shaders do. Here is a brief rundown of the common shader attributes
with which you'll be working:
Color An RGB or HSV value defines what color the shader is when it receives a neu-
tral color light. For more on RGB and HSV, see Chapter 1, “Introduction to Computer
Graphics and 3D.”
Transparency The higher the Transparency value, the less opaque and more see-through
the object becomes.
Although usually expressed in a black-to-white gradient, with black being opaque or solid
and white being totally clear, transparency can have color. In a color transparency, the
shader's color shifts because only some of its RGB values are transparent, as opposed to
the whole.
Ambient Color This color affects the Color attribute of the shader as more ambient light
is created in the scene. Ambient color tends to flatten an object because this attribute
evenly colors the object. This attribute is primarily used to create flat areas and should be
used with care. The default is black, which keeps the darker areas of a surface dark. The
lighter the ambient color, the lighter those areas are. A bright Ambient Color setting flat-
tens out an object, as shown in Figure 7.9.
Figure 7.9
Ambient color
values
Ambient Color = Black
Ambient Color = Medium Gray
Ambient Color = White
Incandescence This is the ability to self-illuminate. Objects that seem to give off or have
their own light, such as an office's fluorescent light fixture, can be given an Incandescence
value. Incandescence doesn't, however, light objects around it in regular renders, nor
does it create a glow. It also serves to flatten the object into a pure color. As you'll see in
Chapter 11, “Maya Rendering,” incandescence can also help light a scene in mental ray's
Search WWH ::




Custom Search