2008

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 Buffer 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 Affects Allows distance from the camera or viewport to affect the
size and/or the intensity of the effect.
Off-Center Affects Allows an effect that is off-center from the camera or
viewport to affect the size and/or the intensity of the effect.
Direction Affects Allows direction of spot lights with respect to the camera
or viewport to affect the size and/or the intensity of the effect.
6396 | Chapter 19 Effects and Environments