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Environment and Atmosphere Effects 271
focal node. You can also press H to display the
Select Objects dialog (page 1–78) from which you
can select objects to use as a focal node.
Remove—Removes the object selected as the Focal
Node.
Use Camer a—Specifies that the focal lengt h from
thecameraselectedintheCameraSelectionlistbe
used to determine the focal point.
Focal Parameters gro up
Custom—Uses the values set in the Focal
Parameters group bo x to determine the properties
of the Depth of Field effect.
Use Camera—Uses the values from the camera
highlighted in the Camera Selection list to
determine focal range, limit, and blur.
Hori z Foca l Loss—Determines the amount of blur
along the horizontal axis when Custom has been
chosen.
Vert Foca l Loss—Controls the amount of blur along
the vertical axis when Custom has been chosen.
Focal Range —Sets the Z distance, in units, to either
side of the focal point in w hich the image will
remain in focus w hen Custom has been chosen.
Focal Li mi t—Sets the Z distance, in units, to either
side of the focal point where blur will reach its
maximumasspecifiedbytheLossspinnerswhen
Custom has been chosen.
Env ir onment a nd
Atmosphere E ffects
Rendering menu > Environment > Environment and
Effects dialog > Environment panel
Environment displays the Environment panel (page
3–272), which is used for setting up atmospheric
andbackgroundeffects.
You can use the environment functions to:
• Setandanimatethebackgroundcolor.
• Use an image in the background of the rendered
scene (screen environment) or use texture
maps as spherical, cylindrical, or shr in k-wrap
environments.
•Setandanimatetheambient light (page 3–908).
• Use atmospheric plug-ins, such as volumetric
light, in the scene.
• Apply exposure controls to renderings.
Atmospher es
A tmospheres are plug-in (page 3–995) components
that create lighting effects such as fog, fire, and s o
on.
Fire Environment Effect (page 3–276)
Fog Environment Effect (page 3–282)
Volume Fog Environment Effect (page 3–284)
Volume Light Environment Effect (page 3–288)
See Environment dialog (page 3–272) for all
environment parameters.
Exposure Controls
Oneofthelimitationsofrenderingperceptually
accurate images is the limited dynamic range
of computer monitors. Dynamic range is the
ratio of the hig hest to lowest intensity a monitor
can produce. In a dark room this ratio is