9

Fog Environment Effect 283
Inter face
The Fog Parameters rollout appears when you
selectFogunderEffectsintheEnvironmentdialog.
The Fog Parameters rollout has the following
controls.
Fog group
Co lor—Sets the color for the fog. Click the color
swatch, and then select t he color you want in the
Color Selector (page 1–161).Youcananimatethe
coloreffectbychangingthefogcoloratanonzero
frame with the A uto Key button on.
Environment Color M ap—Derives the fog color
from a map. You can map the background and the
fog color, you can animate the procedural map
parameters in Track View or Material Editor, and
you can opacity-map the fog.
Thelargebuttondisplaysthenameofthecolor
map, or None if no map is assig ned. The map must
use Environmental mapping coordinat es (page
3–967) (spherical, cylindrical, shr inkw rap, and
screen).
To assign the map you can drag a map from a
Sample slot or Map button in the Mat erial Editor
(or anywhere else in the software; for example,
a projector map button) and drop it on the
Environment Color Map button. A dialog asks
ifyouwanttheenvironmentmaptobeacopy
(independent) or an instance of the s ource map.
Clicking the Environment Color Map button
displays the Material/Map Browser, where you can
choose a map type from the list. To adjust the
environment m ap’s parameters, open the Material
Editor and drag the Environment Color Map
button over an unused sample slot.
Use M ap—To g g l e s t h e eff ec t of this m ap on o r o f f.
Envir onment Opacity M ap—Alters the density of
the fog.
You assign the opacity map, e dit it, and toggle its
effectinthesamewayastheEnvironmentColor
Map.
Fog Backgr ound—Appliesthefogfunctiontothe
background of the scene.
Ty pe—When you choose Stand ard it uses the
parameters in the Standard section and when you
chooseLayeredisselecteditusestheparameters
in the Layered section.
Standard—Enables the Standard group.
Layered—Enables the Layered group.
Standard group
Thins and thickens the fog based on the dist ance
from the camera.
Ex ponential—Increases density exponentially with
distance. When turned off, density increases
linearly with distance. Activate this check box only
when you want to render t ransparent objects in
volume fog.
Tip: IfyouturnonExponential,thisincreasesthe
Step Size value to avoid banding.