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284 Chapter 18: Effects and Environments
Near % —
Sets the density of the fog at the Near
Range (Camera Environment Range parameter).
Far % —Sets the densit y of the fog at the Far Range
(Camera E nvironment Range parameter).
Layered group
Thins and thickens the fog between an upper and
lowerlimit.Youcanhavemultiplelayersoffogby
adding multiple fog entries to the list. Because you
can animate all the fog parameters, you can a lso
animate fog rising and falling, changing density
and color , and add horizon (page 3–953) noise.
Top—Sets the upper extent (in world u nits) of t he
fog layer.
Bottom—Sets the lower extent (in world units) of
the fog laye r.
Density —Sets the overal l density of the fog.
Fa lloff ( Top/B ottom/None)—Adds an exponential
falloff effect so that t he density is reduced to 0 at
either the Top or Bottom of the fog extent.
Hor izon Noise—Turns on the horizon noise system.
Horizon Noise perturbs just the horizon of the fog
layer to add realism.
Size—Scale factor applied to the noise. Larger scale
values make the fog tendrils larger. Default=20.
Tip: If you want tendrils to really pop out, t ry
making the density g reater than 100.
Angle—Determines the affected angle off the
horizon line. For example, if the angle is set to 5 (a
reasonable value), then starting at 5 degrees below
the horizon, the fog will begin to break up.
This effect is mirrored above and below the
horizon, which can produce str ange results when
the height of the fog layer traverses the horizon.
Typically you’d want the fog to be either above or
below the actu al camera horizon. (You can use the
horizon line i n the camera parameters as an aid to
help you position t his.)
Phase—Animating this parameter animates the
noise. If Phase is moving in the positive direction,
then the fog tendrils wil l drift upward (and deform
at the same time). If your fog is above the horizon
you may want to animate Phase in the negative
direction to make the tendrils fall downward.
Volume Fog Environment Ef fect
Rendering menu > Environment > Environment and
Effects dialog > Environment panel > Atmosphere rollout
> Add > Volume Fog
Volume fog added to a scene
VolumeFogprovidesafogeffectinwhichthefog
density is not constan t through 3D space. This
plug-in (page 3–995) provideseffectssuchaspuffy,
cloudy fog that appears to drift and break up in
the w ind.
Volume Fog renders only in Camera or P erspective
views. Orthographic or User v iews don’t render
Volum e F o g e f f e c t s .
Procedures
To use volume f og:
1.
Create a Camera or Perspective view of your
scene.
2. Choose Rendering > Environment.