2008

Link To Light Links the noise effect to its light object, rather than to world
coordinates.
Usually you want noise to look like fog or dust motes in the atmosphere, in
which case, as the light moves, the noise should remain with the world
coordinates. For certain special effects, however, you might want the noise
linked to the light's coordinates. In these cases, turn on Link to Light.
Type Choose one of three types of noise to apply.
■ Regular The standard noise pattern.
■ Fractal An iterative fractal noise pattern.
■ Turbulence An iterative turbulence pattern.
Invert Reverses the noise effect. Dense fog becomes translucent and vice
versa.
Noise Threshold Limits the noise effect. When the noise value is above the
Low threshold and below the High threshold, the dynamic range stretches to
fill 0-1. This makes for a smaller discontinuity (first order instead of 0 order)
at the threshold transition and thus produces less potential
aliasing on page
7708 .
■ High Sets the high threshold. Range=0 to 1.0.
■ Low Sets the low threshold. Range=0 to 1.0.
Uniformity Acts like a high-pass filter: the smaller the value, the more the
volume is transparent with discrete blobs of smoke. By around -0.3 or so your
image begins to look like specks of dust. Because the fog becomes thinner as
this parameter gets smaller, you'll probably need to increase the density or
the volume will start to disappear. Range=-1 to 1
Levels Sets the number of times the noise is iteratively applied. This parameter
is animatable. Enabled only for Fractal noise or Turbulence. Range=1 to 6,
including fractional values.
Size Determines the size of the tendrils of smoke or fog. Smaller values give
smaller tendrils.
6530 | Chapter 19 Effects and Environments