8

Reflection and R efraction Maps 1505
Sub Channel—
Lets you can specify that the map
will use either the Red, Green, or Blue sub-channel
of the specified map channel, or all sub-channels.
Channel Name—After assigning the m aterial with
the Vertex Color map to an object with named
map or vertex-color channels (see
Channel Info
Ut i lity (page 2–1549)
), you can click Update, and
then, from this drop-down list, choose a named
map channel from the object.
Update—Refreshes the contents of the Channel
Name drop-down list. Use Update after applying
the materia l to an object, or after adding channels
to the object.
Note: There could be conflicts if one material
w ith a Vertex Color map is assig ned to objects
w ith different named Map Channels, where one
channel’s name may be displayed in preference to
another’s.
R ef lecti on a nd R ef ra ction
These maps, g rouped as "Other" in the
Material/Map Browser (page 2–1256) ,aremaps
that create reflections and refractions. Each of the
following maps has specific uses:
Flat Mirror (page 2–1505) : Generates reflections
for flat surfaces. You assig n it to faces rather than
to the object as a whole.
Raytr ace (page 2–1508) :Createsaccurate,fully
raytracedreflectionsandrefractions.
Reflect/Refract (page 2–1509) : Generates
reflections or refractions automatically, based on
surrounding objects and the environment.
Thin Wall Refract ion (page 2–1513) : Generates
refractions automatically, simulating objects and
the env ironment seen through a refractive material
such as glass or water.
Fla t M ir r or Ma p
Material Editor > Maps rollout > Click a Map button. >
Material/Map Browser > Flat Mirror
Flat mirror map reflects the ice-cream shop’s interior.
The Flat Mirror (page 3–1036) map produces a
material that reflects surrounding objects when
it is applied to a collection of co planar faces. You
assign it as a material’s
reflection map (page
2–1349)
.
Reflect/Refract maps don’t work well for flat
surfaces because each face reflects part of the
environment based on where its surface normal
points. Using this technique, a large flat face can
reflect only a small part of the env ironment. Flat
Mirror automatically generates a reflection that
encompasses a larger part of the environment, to
better simulate a mirror-like surface.
Rules for Using Flat M irror
Flat Mirror cannot generate reflections correctly
unless you observe these rules:
• Assign Flat Mirror to selected faces only.
Therearetwowaystodothis. Youcanmake
the Flat Mir ror material a sub-material of a
multi/sub-object (page 2–1403) material, or
you can use the Apply To Faces With ID control.