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Lens Effects Rendering Effects 221
Lens Effects Globals rollout, Scene panel
Affect Alpha—Specifies whether or not the Lens
Effect affects the alpha channel of an image when
the image is rendered in a 32-bit file format. The
alpha channel is an extra 8 bits of color (256
colors) that indicate transparency in an image.
Alpha channels are used to composite one image
seamlessly over the top of another. If you want to
composite a Lens Effect, or an image that contains
a Lens Effect, over the top of another image, enable
this option. If you are not rendering to a 32-bit file,
do not enable this option.
Affect Z B uffer—Stores an object’s distance from
the camera. The Z-Buffer is useful for optical
effects. When this option is enabled, the linear
distance of the Lens Effect is recorded, and can
be used in special effects that make use of the
Z-Buffer.
Distance Af fects—Allows distance from the c amera
orviewporttoaffectthesizeand/ortheintensity
of the effect.
Off-Center Affects—Allows an effect that is
off-center from the camera or viewport to affect
thesizeand/ortheintensityoftheeffect.
Direction Affects—Allows direction of spot lights
with respect to the camera or viewport to affect
thesizeand/ortheintensityoftheeffect.
The size and intensity of the effect are at a
maximum when the light is pointed at the camera
(or view port).
Occlusion group
Occlusion is used to determine when a Lens Effect
will be affected by an object that comes between
the effect and the camera. By using two spinners
to determine occlusion you can have scene objects
realistically affect the look of your effect . The outer
radius wi ll determine when another scene object
will begin to occlude and the inner radius will
determine when the scene object wi l l cause the
effect to reach maximum o cclusion.
Inner Radius—Sets the inner radius around the
effect that another scene object must intersect in
order to completely occlude the effect.
Outer R a di us—Sets the outer radius around the
effect that another scene object must intersect in
order to begin to occlude the effect.
Size—Decreases the size of the effect when b eing
occluded.
Intensity—Decreases the intensity of the effect
when being occluded.
Affected by Atmosphere—Allows Atmospheric
Effects to occlude Lens Effects.