Houdini 20.0 Nodes VOP nodes

Cloud Noise VOP node

Generates 1D noise used for cloud noise generation.

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Since 20.0


This node is a custom noise fractal that distorts the noise with each fractal iteration to provide more billowy looking noise for cloud generation.



Sets the data types this node expects for the inputs, and the data type of the output. This allows you to integrate the noise with various other VOPs.

Cloud Noise

Noise Type

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


Produces a bumpy output, similar to alligator skin. While this node is not distorted by the fractal iterations, it is useful to create finer bumpy cloud details.


Noise where the visual details are the same size. Wikipedia article

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


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

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):


The generated noise will be roughly from 0 to this value.

Element Size

Uniform scale of elements in the noise.

Click the Per Component button for separate scales along each axis.

Element Scale

Turn on the Per Component button to scale the Element Size separately across each axis.


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.

You can animate the noise using an expression such as $T * 0.25 here. This is faster to compute than Animate Noise, but gives the visual effect of “panning” across the noise field.

Click the Per Component button for separate additional offsets along each axis.


Turn on the Per Component button to add the a separate offset along each axis.

Worley Details

Add Worley Details

When turned on, a worley noise is combined with the noise pattern (specified by Noise Type) to give puffy cloud noise. Enabling this, will largely diminish the distortion effect (specified by Distortion).

Noise pattern with added worley noise:


Controls the amount of mixing between the noise pattern (specified by Noise Type) and the worley noise. A value of 0 means no worley noise is applied to the noise pattern.


Controls how fast the edges of the noise pattern turn to zero. The larger the value, the more the edges are eroded creating smaller and smaller cloud patches.

Element Size Scale

Multiplier on the Element Size parameter that effects the worley noise pattern.


Max octaves

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 frequency increment between iterations of fractal noise added to the basic output. Note that you can use a negative value.


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.



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):

Droop Direction

The direction in which the noise is warped.


Remaps the values between -1 and 1 and flips values below 0 to the positive range, so all valleys become peaks.


Animate Noise

Vary the generated noise with time. To use this feature, you must set the Signature to 4D Input, 1D Noise.

Applying animation this way on geometries with millions of element count is slower to compute than using expressions such as $T * 0.25 in the Offset parameter to “pan” across the noise field.

Pulse Duration

When Animated Noise is turned on, this controls the rate of change of the noise pattern.

Output Correction


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).


Computes the complement of the noise by subtracting the generated noise from 1.

VOP nodes