Fractal Noise effect
The Fractal 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, lava, or vapor.
The Evolution controls create subtle changes in the shape of the fractal noise. Animating these controls results in smooth changes of the noise over time, creating an effect such as passing clouds or flowing water.
This effect works with 8-bpc, 16-bpc, and 32-bpc color.
Controls
- Fractal Type
- The noise is created by generating a grid of random numbers for each noise layer (where the number of noise layers is specified by Complexity). 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 layer’s 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 of 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 of 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 fractal 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 fractal noise is generated by combining layers of noise.
The Sub Settings control how this combination occurs and how the
noise layers’ properties 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, Rotation, and Offset
- The scale percentage, angle, and position of a noise layer relative to the previous noise layer.
- Center Subscale
- Calculates each noise layer from the same point as the previous layer. This setting can result in the appearance of duplicated noise layers stacked on top of each other.
- 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 that at 1 revolution, which
is different from that at 2 revolutions, and so on. To return the
Evolution setting to its original state (for example, to create
a seamless loop), use the Cycle Evolution option.
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.
To create a seamless loop, use Cycle Evolution, and set Evolution keyframes at full revolutions with no degrees—partially completed revolutions may interrupt the loop.
- Evolution Options
-
Options for Evolution.
- Cycle Evolution
-
Creates a cycle of Evolution that loops over the set amount
of time. This option forces the Evolution state to return to its
starting point, creating a smooth progressive cycle, a nonrepeating
cycle, or a loop segment.
To ensure that a cycle completes full revolutions, choose a Cycle value that either matches or is evenly divisible by the number of revolutions set for Evolution.
- Cycle (in Revolutions)
-
Specifies the number of revolutions that the noise cycles through
before it repeats. The speed of these Evolution cycles is determined
by the amount of time between Evolution keyframes. This option affects
only the evolution of the noise, not Transform or other controls.
For example, if you view two identical states of noise with different
Size or Offset settings, they don’t appear the same.
Note: Cycle is available only if Cycle Evolution is selected.
- Random Seed
- Sets a unique random value from which to generate the noise. Animating the Random Seed results in flashing from one set of noise to another (within that fractal type). For smooth transition of the noise, use the Evolution option.
You
can easily create new fractal 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. Instead of animating
Evolution over the entire composition, save rendering time by prerendering
and looping one short Evolution cycle for the duration you want. - Opacity
- Specifies the opacity of the noise.
- Blending Mode
-
Specifies
an operation between the fractal noise and the original image. These
blending modes are identical to the ones in the Modes column in
the Timeline panel, with the following three 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.