The type of noise to generate. Different algorithms give noise with different characteristics.

Fast

The default. A faster and more interesting variant of Perlin noise.

Frequency is scaled by 1.25.

Sparse Convolution

Sparse Convolution noise is similar to Worley noise. Does not have artifacts at grid points.

Frequency is scaled by 1.25.

Alligator

Produces a bumpy output. Named for its alleged resemblance to alligator skin.

Frequency is scaled by 1.64.

Perlin

A noise where the visual details are the same size. Wikipedia article

Perlin Flow

A noise that’s stable over time, like a rotated Perlin noise, useful to create noise that seems to swirl and flow smoothly across time. Use the Flow rotation parameter below to control the rotation.

Simplex

A noise similar to Perlin but the noise lattice is on a tetrahedral mesh rather than a grid. This can avoid the grid patterns often visible in Perlin noise.

Worley Cellular F1

Produces cellular features similar to plant cells, ocean waves, honeycombs, cratered landscapes, and so on. Wikipedia article

Worley Cellular F2-F1

A variant of Worley noise that produces blunted and cornered features.

Manhattan Cellular F1

A variant of Worley F1 noise that uses Manhattan distance calculation. Useful when you want unusual-looking noise.

Manhattan Cellular F2-F1

A variant of Worley F2-F1 noise that uses Manhattan distance calculation. Useful when you want unusual-looking noise.

Chebyshev Cellular F1

A variant of Worley F1 noise that uses Chebyshev distance calculation. Useful when you want unusual-looking noise.

Chebyshev Cellular F2-F1

A variant of Worley F2-F1 noise that uses Chebyshev distance calculation. Useful when you want unusual-looking noise.

Perlin Cloud

Generates perlin noise based cloud pattern influenced by the Distortion parameter.

Perlin noise with Distortion set to -1 (left) and +1 (right):

Simplex Cloud

Generates simplex noise based cloud pattern influenced by the Distortion parameter. Simplex noise similar to Perlin, but the noise lattice is on a tetrahedral mesh rather than a grid. This can avoid the grid patterns often visible in Perlin noise.

Simplex noise with Distortion set to -1 (left) and +1 (right):

Fast Simplex Cloud

Generates fast simplex noise based cloud pattern influenced by the Distortion parameter. This simplex noise function uses a different lattice structure and a cheaper accumulation method.

Simplex noise with Distortion set to -1 (left) and +1 (right):

Controls the effect of the distortion. Large values will create larger billowy details in the pattern, but might create unrealistic looking cloud patterns.

Uniform scale of elements in the distortion noise. This scale is relative to Element Size, which controls the overall pattern size.

Offset within the evaluated noise field (added to each axis). If you have the general noise effect you want, but want to get a different set of values for a different look, try changing the offset.

This value controls how much the medium grey (noise values around 0.5) is pulled towards zero (if Bias is less than 1) or pulled towards one (if Bias is greater than 1). A value of 0.5 leaves the noise values unaffected.

Controls how much the medium greys (noise values around 0.5) are pulled together, while values around 0 and 1 are pulled apart. The value of 0.5 leaves the noise values unaffected.

Controls the overall gamma of the generated noise. Values less than 1 will darken the noise, increasing the range of values in originally bright areas. Conversely, values greater than 1 will stretch out the range of values for originally dark areas, which will increase the overall brightness of the noise.

This value expands or shrinks the overall range of tonal values. Particularly, each noise value is pushed towards (if Contrast is less than 1) or away from (if Contrast is greater than 1) medium grey (noise values at 0.5).

Shifts the internal noise pattern range (roughly 0-1) to displace the volume in the opposite direction of the surface normal as well. A value of 0.25 will shift this range to -0.25-0.75.

When the Value Offset is larger than zero, this will set any negative noise value back to zero. Use this to create a displacement pattern that has areas without any displacement.

Inverts the generated noise pattern.

Controls how much the noise is distorted in the direction of decreasing noise values if Distortion is greater than 1, and in the direction of increasing noise values if Distortion is less than 1. When worley details are added to the noise pattern, the effect of distortion are largely diminished.

Distortion with a value of 1:

Distortion with a value of -1:

How much to stretch the noise in each direction. The advantage of using this instead of Element Size is that it preserves some details unstretched, making the stretched noise pattern more natural looking.

Comparing Element Scale of 3 (left) to Stretch value of 3 (right) along the X-axis:

Warps the generated noise such that the noise pattern is bending or hanging towards the given droop direction.

Noise pattern without (left) and with droop applied (right):

The direction in which the noise is warped.

Applies additional noise offset to the main noise to create finer details.

Controls the effect of the advection, large values will advect the noise more. This is a multiplier on the noise amplitude (given by Amplitude).

Uniform scale of elements in the noise. This is a multiplier on the noise element size (given by Element Size).

Offset within the evaluated advection noise field (added to each axis). If you have the general noise effect you want, but want to get a different set of values for a different look, try changing the offset.

The number of iterations of distortion to add to the output of the basic noise. The more iterations you add, the more “detailed” the output. Note that the output may have fewer octaves than this parameter (that is, increasing the parameter will eventually stop adding detail), because the node eventually stops when there’s no more room to add more detail in the output.

The scale increment between iterations of fractal noise added to the basic output. The higher the value the larger the “jaggies” added to the output. You can use a negative value for roughness.

These many numbers of noise patterns are generated in one iteration; each with different noise offset. Increasing this value will generate somewhat more filled and larger displacement noise.

Controls how the internal billowy noise is sampled based on position, greatly effecting the look of the displacement. The value of 1 means that the noise is sampled according to the closest point on the surface defined by the signed distance field of the incoming volume. Just as with displacing a geometry along its normal, the generated peaks have no detail along the axis of displacement. This visual drawback can be eliminated by enabling multiple billowy noise iterations (given by Iterations). A value of 0 means that the noise is sampled using the world position of each voxel. While this method applies displacement in all directions, by increasing the noise amplitude (given by Amplitude), this method can very easily lead to numerous isolated fog pieces around the main cloud.

When turned on, the displacement will decrease based on the surface normal direction and the up vector.

User specified up vector for noise falloff.

When this is turned on and multiple iterations are set (given by Iterations), this will use the accumulated noise pattern in each iteration as a scalar on noise amplitude of the next iteration.

To apply noise displacement to the incoming volume, the active area must be expanded. The expansion amount is automatically calculated based on the given settings, and this value is a multiplier on top of that value. If you notice artifacts in the generated volume, the displacement amount is probably larger than expansion distance, in which case increase this number to create a larger active region.

When this is turned on, it resamples the incoming volume in each iteration. This parameter is useful when multiple iterations are set (given by Iterations) to increase the number of voxels in the volume with each iteration (given by the Voxel Size Scale parameter on the Attenuation tab). It is rather common first to use a low-resolution incoming volume for testing. However, when you switch the input volume for a higher resolution version, the displacement features might look visually different. To preserve the features, leave the incoming resolution the same while this parameter and multiple iterations are enabled.

To find the normals of the incoming volume, the volume has to be converted to a signed distance field volume. When this is turned on, a lower resolution volume is used than generated the SDF field, speeding up the conversion process. Increased values will generate lower resolution SDF field.

The crossing point of this value in the volume will be converted to the iso surface. For example, 0 for signed distance fields or 0.5 for fog volumes.

When Iterations and this parameter are turned on, this controls the amplitude reduction for each iteration.

When Amplitude is set to 1 and this parameter is 0.35, the table shows the final amplitude value for each iteration:

When Iterations and this parameter are turned on, this controls the element size reduction for each iteration.

When Iterations and this parameter are turned on, this controls the reduction in the number of noises for each iteration.

When Iterations and this parameter are turned on, this controls the worley blend reduction for each iteration.

When Iterations and this parameter are turned on, this controls the worley erosion reduction for each iteration.

When Iterations and this parameter are turned on, this controls the bias reduction for each iteration.

When Iterations and this parameter are turned on, this controls the gain reduction for each iteration.

When Iterations and this parameter are turned on, this controls the gamma reduction for each iteration.

When Iterations and this parameter are turned on, this controls the contrast reduction for each iteration.

When Iterations and this parameter are turned on, this controls the number of octave reductions for each iteration.

When Iterations and this parameter are turned on, this controls the roughness reductions for each iteration.

When Iterations and this parameter are turned on, this controls the distortion reductions for each iteration.

When Iterations and this parameter are turned on, this controls the droop reductions for each iteration.

When Iterations and this parameter are turned on, this controls the stretch reductions for each iteration.

When Iterations and this parameter are turned on, this controls the rest position bias reductions for each iteration.

When Iterations and this parameter are turned on, this controls the up vector bias reductions for each iteration.

When Iterations and this parameter are turned on, this controls the voxel size reductions for each iteration.

The name of the volume to be used as density for generating the billowy noise. Usually you should leave it as density.

The name of the volume to be used as mask generating the billowy noise. Usually you should leave it as mask.