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Far Attenuation group
You can set the attenuation range for a photometric light. Strictly speaking,
this is not how real-world lights behave, but setting an attenuation range can
help improve rendering time dramatically.
TIP If your scene has a large number of lights, use Far Attenuation to limit the
portion of the scene each light illuminates. For example, if an office area has rows
of overhead lights, you could set Far Attenuation ranges to keep the lights’
illumination from being calculated when you render the reception area instead of
the main office. As another example, a staircase might have recessed lights on
each stair, as many theaters do. Setting a small Far Attenuation value for these
lights can prevent their (negligible) illumination from being calculated when you
render the theater as a whole.
Use Enables far attenuation for the light.
Show Displays the far attenuation range settings in viewports. For spotlight
distribution, attenuation ranges appear as lens-shaped sections of the cone.
For other distributions, the ranges appear as spheres. By default, Far Start is
light brown and Far End is dark brown.
Start Sets the distance at which the light begins to fade out.
End Sets the distance at which the light has faded to zero.
Shape/Area Shadows Rollout
Create panel > Lights > Photometric Lights > Create a light. > Modify panel >
Shape/Area Shadows rollout
Create panel > Lights > Photometric Lights > Create a light. > Modify panel >
Shape/Area Shadows rollout
The Shape/Area Shadows rollout lets you choose the light shape used to
generate shadows.
5040 | Chapter 18 Lights and Cameras