An Inverse Square Decay more closely resembles
the decay of real-world light, and it is a stronger rate of decay than Inverse Decay. Use this
decay rate to drop off the effect of a light quickly before it reaches too far into the scene;
however, you will need a stronger Multiplier value to increase your light??™s intensity to
compensate for the much faster decay.
In Figure 10.37, you can quickly see and set the start of a decay in spot and directional
lights by changing the Start value in the Decay section of the rollout.
In the following image (Figure 10.38) you can see a decay start that is closer to the light
and its effect on the render in the top-left corner.
The start of the decay is moved closer to the spheres in Figure 10.39.
Figure 10.39
A decay start closer
to the spheres
Figure 10.38
A decay start
common light parameters ?– 477
Light Attenuation
Light attenuation is another way to diminish the intensity of a light over distance. With
attenuation, however, you have more implicit control on the start and end of the fade,
and you can specify an area where the light fades in and then fades out. To do this, set the
Attenuation distances to the desired effect.
NEAR ATTENUATION GROUP
The following values set the distances where the light fades into existence:
Start The distance at which the light starts to fade in.
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