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Material Components 1399
Several different shaders are available. Some of
these are not available for the Raytrace material, as
indicated below. Blinn is the most general-purpo se
of these shaders. The others have special purposes,
especially regarding how the material creates
high lights.
• Anisotropic (page 2–1480)
Createssurfaceswithnoncircular,"anisotropic"
high lights; good for modeling hair, glass, or
metal.
• Blinn (page 2–1480)
Creates smooth surfaces with some shininess; a
general-purpose shader.
• Metal (page 2–1481)
Creates a lustrous metallic effec t.
• Multi-Layer (page 2–1481)
Creates more complex highlights than
Anisotropic by layering two anisotropic
high lights.
Not available for Raytrace material.
• Oren-Nayar -Blinn (page 2–1482)
Creates good matte surfaces such as fabric or
terra-cotta; similar to Blinn.
• Phong (page 2–1480)
Creates smo oth surfaces with some shininess;
similar to Blinn, but doesn’t handle highlights
(especially glancing highlig hts) as well.
• Strauss (page 2–1483)
Creates both nonmetallic and metallic surfaces;
has a simple set of cont rols.
Not available for Raytrace material.
• Translucent (page 2–1484)
Translucent shading is similar to Blinn shading,
butitalsoletsyouspecifytranslucency,where
lightisscatteredasitpassesthroughthe
material. You can use translucency to simulate
frosted and etched g lass.
Not available for the Raytrace material.
Material Components
Amaterial’scomponentsdescribeitsvisual
and optical properties. The components in
the Architectural material (page 2–1535) are
based on physical qualities; for example, diffuse
color, shininess, transparency, and so on. The
components in a Standard material (page 2–1465)
include color components, highlight controls,
self-illumination, and opacity. Like the Standard
material, the Raytrace material (page 2–1512) uses
anonphysicalmodeltodescribesurfaces.
Standard and Raytrace material components vary
depending on which shader (page 2–1398) you use.
Yo u c a n a s s i g n m a p s t o m o s t c o m p o n e n t s ,
including color components such as Diffuse,
and value components such as Transparency or
Opacity. Maps can incr ease the complexity and
realism of the material’s appearance.
Light s a nd S hading
Materials work in combination with lights (page
2–1272). T he intensity of light that falls on a
surface determines the intensity of color to display.
Three factors contribute to the intensity of light
where it falls on an object:
• Light i ntens i ty: A light’s original intensity at
its point of origin.
• Angle of in cidence: The more a surface
inclines away from the light source, the less light
it receives and the darker it appears. The angle
between a ray of light and the face normal (page
3–980) of a surface is the angle of incidence for
that face.
When the angle of incidence is 0 degrees (that
is, the light strikes the face per pendicularly),
thefaceisilluminatedatfullintensityunless