8

Fog Environment Effect 279
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 the color you want in the
Color Selector (page 1–157) .Youcananimatethe
coloreffectbychangingthefogcoloratanonzero
frame with the Auto Key button on.
Environment Color M ap—Derives the fog color
from a map. You can map the background and the
fog color, y ou 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 assigned. The map
must use Environmental
mapping coordinates
(page 3–1061)
(spherical, cylindrical, shrinkwrap,
and screen).
To assign the map you can drag a map from a
Sample slot or Map button in the Material 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 source map.
Clicking the Environment Color Map button
displays the Material/Map Browser, where you c an
choose a map type from the list. To adjust the
environment map’s parameters, open the Material
Editor and drag the Environment Color Map
button over an unused sample slot.
Use M ap —Togg l e s t h e effec t of t h i s m a p on o r off.
Envir onment Opa city M ap—Alters the density of
the fog.
You assign the opacity map, edit it, and togg le its
effectinthesamewayastheEnvironmentColor
Map.
Fog Backgroun d—Appliesthefogfunctiontothe
background of the scene.
Ty pe—When you choose Standard 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 distance
from the camera.
Ex ponential—Increases densit y exponentially with
distance. When turned off, density increases
linearly with distance. Activate this check bo x only
when you want to render transparent objects in
volume fog.
Tip: IfyouturnonExponential,thisincreasesthe
Step Size value to avoid banding.