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Turbulent Noise effect
The Turbulent
Noise effect uses Perlin noise to create grayscale noise that you
can use for organic-looking backgrounds, displacement maps, and
textures, or to simulate things like clouds, fire, lava, steam,
flowing water, or vapor.
The Turbulent Noise effect is essentially a modern, higher-performance
implementation of the Fractal Noise effect. The Turbulent Noise
effect takes less time to render, and it’s easier to use for creating
smooth animations. The Turbulent Noise effect also more accurately
models turbulent systems, with smaller noise features moving more
quickly than larger noise features. The primary reason to use the
Fractal Noise effect instead of the Turbulent Noise effect is for
the creation of looping animations, since the Turbulent Noise effect
doesn’t have Cycle controls.
Note: Because the controls for the two effects are nearly identical,
you can use most instructions and tutorials created for the Fractal
Noise effect to instead guide your use of the Turbulent Noise effect.
(See Fractal Noise effect.)
The Evolution controls create subtle changes in the shape of
the noise. Animating these controls results in smooth changes of
the noise over time, creating results that resemble, for example,
passing clouds or flowing water.
This effect works with 8-bpc, 16-bpc, and 32-bpc color.
Controls- Fractal Type
- The fractal noise is created by generating a grid of random numbers
for each noise layer. The Complexity setting specifies the number
of noise layers. The Fractal Type setting determines the characteristics
of this grid.
- Noise Type
- The type of interpolation to use between the random values
in the noise grid.
- Invert
- Inverts the noise. Black areas become white, and white areas
become black.
- Contrast
- The default value is 100. Higher values create larger, more
sharply defined areas of black and white in the noise, generally
revealing less subtle detail. Lower values result in more areas
of gray, softening or muting the noise.
- Overflow
- Remaps color values that fall outside the range of 0–1.0,
using one of the following options:
- Clip
- Remaps values so that any value above 1.0 is displayed as
pure white, and any value below 0 is displayed as pure black. The
Contrast value influences how much of the image falls outside this
range. Higher values result in a mostly black and/or white image
with less gray area. Therefore, higher contrast settings display
less subtle detail. When used as a luma matte, the layer has sharper, better-defined
areas of transparency.
- Soft Clamp
- Remaps values on an infinite curve so that all values stay
in the range. This option reduces contrast and makes noise appear
gray with few areas of pure black or pure white. When used as a
luma matte, the layer contains subtle areas of transparency.
- Wrap Back
- Remaps triangularly, so that values above 1.0 or below 0
fall back into the range. This option reveals subtle detail when
Contrast is set above 100. When used as a luma matte, the layer
reveals more detailed textured areas of transparency.
- Allow HDR Results
- No remapping is performed. Values outside the range of 0-1.0
are preserved.
- Transform
- Settings to rotate, scale, and position the noise layers.
The layers appear as if they are at different depths if you select
Perspective Offset.
- Complexity
- The number of noise layers that are combined (according to
the Sub Settings) to create the noise. Increasing this number increases
the apparent depth and amount of detail in the noise.
Note: Increasing
Complexity results in longer rendering times. If appropriate, try reducing
the Size rather than increasing Complexity to achieve similar results
and avoid longer rendering. A trick to increase apparent complexity
without increasing rendering time is to use a negative or very high
Contrast or Brightness setting and choose Wrap Back for Overflow.
- Sub Settings
- The noise is generated by combining layers of noise. The
Sub Settings control how this combination occurs and how the properties
of the noise layers are offset from one another. Scaling successive
layers down creates finer details.
- Sub Influence
- How much influence each successive layer has on the combined noise.
At 100%, all iterations have the same amount of influence. At 50%,
each iteration has half as much influence as the previous iteration.
A value of 0% makes the effect appear exactly as if Complexity is
1.
- Sub Scaling
- The scale percentage of a noise layer relative to the previous
noise layer.
- Evolution
- Uses progressive revolutions that continue to change the
image with each added revolution. This method is unlike typical
revolutions that refer to a setting on the dial control for which
the result is the same for every multiple of 360°. For Evolution,
the appearance at 0° is different from the appearance at 1 revolution,
which is different from the appearance at 2 revolutions, and so
on.
You can specify how much the noise evolves over a period
of time by animating Evolution. The more revolutions within a given
amount of time, the more rapidly the noise changes. Large changes
in the Evolution value over a short period of time may result in
flashing.
- Evolution Options
-
- Turbulence Factor
- The amount by which the speed of smaller noise features differs
from the speed of larger noise features. A value of 0 makes the
movement of the noise resemble the noise generated by the Fractal
Noise effect, in which smaller noise features move at the same speed
as larger noise features. A larger value makes the multiple layers
of noise appear to roil in a manner more like that of natural turbulence
in a fluid.
- Random Seed
- Sets a random value from which to generate the noise. Animating
the Random Seed property results in flashing from one set of noise
to another (within that fractal type), which is usually not the
result that you want. For smooth animation of noise, animate the
Evolution property.
 You
can easily create new noise animations by reusing previously created Evolution
cycles and changing only the Random Seed value. Using a new Random Seed
value alters the noise pattern without disturbing the Evolution
animation. - Opacity
- The opacity of the noise.
- Blending Mode
- The blending operation between the noise and the original image.
These blending modes are identical to the ones in the Modes column
in the Timeline panel, with the following exceptions:
- None
- Renders the fractal noise only and does not composite on
the original layer.
- Hue
- Renders the fractal noise as hue values instead of grayscale.
The Saturation and Lightness of the original layer are maintained.
If the original layer is grayscale, nothing happens.
- Saturation
- Renders the fractal noise as saturation values instead of
grayscale. The Hue and Lightness of the original layer are maintained.
If the original layer is grayscale, nothing happens.
For
a description of each blending mode, see Blending mode reference.
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