9

Segment 1009
Segment
The arrow and highlight indicate a single segment in a spline.
The portion of a NURBS point curve between
two of its control points, or the portion of a spline
between two vertices. (NURBS CV curves don’t
have segments, as t heir control vert ices don’t lie
on the curve.)
Self-Illumination
The lamp on the right uses self-illumination to brighten the
bulb and the glass panes.
Self-Illumination creates the illusion of
incandescence by replacing any shadows on the
surfacewiththediffusecolor.At100percent,the
shadows are completely replaced by the diffuse
color, creating the illusion of self-illumination.
Unless you use environmental effects, only lights
illuminate your scene; they don’t appear in the
rendering. You can use self-illuminated materials
on objects that represent lights to provide things
like car head lights, and so on.
A self-illumination map lets you use a map
to affect the intensity in different areas of the
self-illuminated surface. Like many other m ap
types, only the intensity of the map values affects
self-illumination. White provides the most, w hile
black blocks the illumination completely.
It’s often a good idea to design a self-illumination
map to match your diffuse map. For example, the
diffusemapmighthavesmall,yellowrectangles
to represent windows, while the self-illumination
map consists of matching white rectangles against
black to illuminate the yellow windows.
Tip: To have an object behave as an actual light
source (fo r example, a spline that models a neon
light), use t he scanline renderer (page 3–38),
photometric light s (page 2–1301) with a radiosity
solution (page 3–51), and assign an Advanced
Lighting O verride material (page 2–1601) to make
the object luminous.
Shaders (mental ray Renderer)
In mental ray, a shader is a function that calculates
light effects. There can be shaders for lights,
cameras (lens shaders), materials, shadows, and
so on.
In 3ds Max, the mental ray translator provides the
functionality of light and camera shaders. Material
shaders correspond to 3ds Max materials.
A number of sh aders are provided with 3ds Max.
See mental ray Shaders (page 2–1710), mental ray
Connection Rollout (page 2–1461),andmental ray
Materials (page 2–1543).