Attribute Noise 2.0 geometry node

Adds or generates noise in geometry attributes.

On this page	Overview Tips and notes Parameters
Since	18.5

Overview ¶

The Attribute Noise SOP provides a simple interface for quickly adding coherent noise to float and vector attributes, without needing to create VOP networks or write VEX code. All of the models provided by the Unified Noise VOP can be used with this node.

Tip

While this node has a simple and straightforward interface, the following nodes might allow for a finer control over modifying common attributes such as: pscale, life, variant, v, and N.

Tips and notes ¶

If an attribute exists, you can overwrite or combine the noise with the current values according to the Operation parameter. If an attribute doesn’t exist, this node will create it.

Parameters ¶

General

Group

The subset of the input geometry to apply the modifications to. Leave this blank to affect all elements. The type of the group is controlled by the Attribute Class parameter.

Blend

Blends between the incoming attribute and the output attribute value. A blend of 0 means that no adjustment takes place: the incoming attribute value is the output value. Likewise, a value of 1 will output the adjusted value, ignoring the initial value. Blending can be done either by uniform value (Constant) or by value of the Blend Attribute (when the menu on the right of this parameter is set to Use Attribute).

Blend Attribute

A float attribute between the range 0 to 1 to use as blend value. This attribute must be present on the appropriate elements (as set by Attribute Class). A blend value of 0 means that no adjustment takes place: the incoming attribute value is the output value. Likewise, a value of 1 will output the adjusted value, ignoring the initial value.

Attribute Type

Choose whether the attributes are float attributes or vector attributes. The node will switch to generate 1D or 3D noise according to this choice.

Attribute Names

The name of the attribute to generate noise into. The class of attribute (such as point, face, or vertex) is controlled by the Attribute Class parameter. If the attribute does not exist, this node will create it. You can specify a space-separated list of names to add noise to multiple attributes at once.

Component Scope

When the attributes are vector attributes, specifies which vector components will be changed by this node. This filter applies as the last step on the adjustment value generation and it is useful to limit the dimension of the noise.

Attribute Class

The level at which to look for/create the listed attributes: detail (whole geometry), primitives (faces), points, or vertices.

Noise Along Vector

When the attributes are vector attributes, and the checkbox is on, the direction of the noise will be controlled by the Vector Attribute parameter and the noise will change the length of this vector. This is useful when you need to displace geometry along it’s normal direction.

Vector Attribute

The attribute to use to specify the direction of the generated noise when Noise Along Vector is enabled. By default it will displace the geometry along it’s normal vector.

Noise Range

Range Values

How to compute the minimum and maximum noise values. This menu lets you quickly set up common ranges (from zero to N, or from -N to N).

Positive

From 0 to the Amplitude value.

Zero Centered

From negative Amplitude to positive Amplitude.

Min/Max

Explicitly set Min Value and Max Value.

Min Value	Max Value	Custom Range
0	1	0 to 1
5	10	5 to 10
-5	7	-5 to 7

Negative

From negative Amplitude to 0 value.

Min + Range Length

The range contains all values between Min Value and Min Value + Range Length. For instance, if Min Value is 2 and Range Length is 5, the minimum and maximum limits of the range will be 2 and 7, respectively.

Min Value	Range Length	Custom Range
0	1	0 to 1
5	10	5 to 15
-5	7	-5 to 2

Middle ± Range Length

The range contains all values between Middle Value - Range Length and Middle Value + Range Length. For instance, if Middle Value is 8 and Range Length is 4, the minimum and maximum limits of the range will be 4 and 12, respectively.

Middle Value	Range Length	Custom Range
0	1	-1 to 1
5	5	0 to 10
-5	7	-12 to 2

Note

Behavior in this mode is different from Middle ± Range Length on the attribute adjust nodes, where the resultant interval spans from Middle Value - Range Length / 2 to Middle Value + Range Length / 2.

Operation

How to combine the generated noise with an existing attribute value. If the target attribute does not exist on the input geometry, this menu is ignored.

Set Initial

If the attribute doesn’t exist, set its value. If the attribute does already exist, don’t modify it.

Set Always

Overwrite any existing value.

Add

Add the generated noise value to the existing value.

Subtract

Subtract the generated noise value from the existing value.

Multiply

Multiply the generated noise value by the existing value.

Minimum

Use the lower of the generated noise value and the existing value.

Maximum

Use the higher of the generated noise value and the existing value.

Amplitude

When Range Values is Positive Values, the generated noise is from 0 to this value. When Range Values is Negative Values, the generated noise is from the negative of this value to 0 value. When Range is Zero Centered Values, the generated noise is from negative this value to positive this value.

When Attribute Type is Vector, click the Per Component button for separate amplitudes along each axis.

Amplitude Scale

When Attribute Type is Vector and you turn on the Per Component button, this lets you scale the Amplitude separately across each axis.

Min Value

When Range Values is Min/Max, the lower limit of the range.

When Attribute Type is Vector, click the Per Component button for separate minimums along each axis.

Min Value Scale

When Attribute Type is Vector, Range Values is Min/Max, and you turn on the Per Component button, this lets you scale the Min Value separately across each axis.

Max Value

When Range Values is Min/Max, the higher limit of the range.

When Attribute Type is Vector, click the Per Component button for separate minimums along each axis.

Max Value Scale

When Attribute Type is Vector, Range Values is Min/Max, and you turn on the Per Component button, this lets you scale the Max Value separately across each axis.

Middle Value

When Range Values is Middle ± Range Length, this value lies in the center of the custom range.

When Attribute Type is Vector, click the Per Component button for separate middle values along each axis.

Middle Value Scale

When Attribute Type is Vector, Range Values is Middle ± Range Length, and you turn on the Per Component button, this lets you scale the Middle Value separately across each axis.

Range Length

When Range Values is Min + Range Length or Middle ± Range Length, sets the length of the custom range.

When Attribute Type is Vector, click the Per Component button for separate the range along each axis.

Range Length Scale

When Attribute Type is Vector, Range Values is Min + Range Length or Middle ± Range Length, and you turn on the Per Component button, this lets you scale the Range Length separately across each axis.

Output Raw Value

When this is on, the distribution of values is non-uniform, being more likely to fall near the center of the range than the edges. When this is off, values have a more uniform distribution across the range.

This example shows noise where the Element Size is animated. The left side has this parameter on, the right side has this parameter off.

Enable Remap Ramp

Turn this on to shape the output of the noise with a ramp.

Remap Ramp

When Enable Remap Ramp is on, this ramp lets you control the output of the noise function. The horizontal axis represents the range (minimum on the left, maximum on the right). The vertical axis represents the number to output when the noise function generates that point within the range.

The default ramp (diagonal from bottom-left to top-right) outputs each number “as itself”.

Value Correction

Bias

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.

Gain

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.

Gamma

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.

Contrast

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).

Noise Pattern

Noise Type

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):

Location Attribute

The node generates values for each element by sampling a noise field at the location specified by this vector attribute on the incoming geometry. If this is P (point position, the default), the points of the geometry will appear to swim through the noise. If you want the noise to “stick” to the points, you can copy the initial point positions into a rest attribute and use that attribute here instead.

Element Size

Uniform scale of elements in the noise.

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

Element Scale

When you turn on the Per Component button, this lets you scale the Element Size separately across each axis.

Offset

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, which may or may not be acceptable.

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

Offset

When you turn on the Per Component button, this lets you add the a separate offset along each axis.

Use VEXpression

Turn this checkbox on to use a VEXpression to override parameters based on arbitrary attribute values.

VEX Expression

A VEX expression that can override noise parameters based on arbitrary attributes on the geometry. The comments in the default snippet (and the “Pass Through” preset in the menu to the right of the editor) show which parameters you can override, currently pos, elementsize, and offset.

For instance, you can use pos += v@noise_offset; to offset the sampling location by the value of each element’s noise_offset vector attribute. As another example, using pos = v@noise_offset; will overwrite the incoming value with the noise_offset attribute: this is effectively the same as using noise_offset as the Location Attribute.

Animation

Animate Noise

Vary the generated noise with time. Some noise types do not support this feature.

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 on, this controls the rate of change of the noise pattern.

Fractal

The fractal controls let you add additional fractal noise on top of the output of the basic noise type.

Fractal Type

None

Does not add any additional noise on top of the basic noise.

Standard

Adds pseudo-random noise on top of the basic output.

Terrain

Adds noise like “Standard” but dampens the noise in the valleys, which can be useful for generating mountainous terrain.

Hybrid

Like terrain, but with more sharpness in the valleys.

The following parameters are available when Fractal type is anything except None.

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.

Lacunarity

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

Roughness

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.

Warping

Lattice Warp and Gradient Warp are two methods for adding “fractal-ness” to the basic noises by warping the noise space.

Lattice Warp

Adds “stringiness” or “wiriness” to standard noise.

Lattice Warp Size

Controls base feature size of the generated noise. The value applies to each axis.

Gradient Warp

Widens the peaks or valleys of the noise output.

Accumulate Lattice Warp

Accumulates the warp for each iteration (octave) of added fractal noise. This can add interesting smudgy effects when used in images, and interesting landmarks when used for terrain.

Accumulate Gradient Warp

Accumulates the warp for each iteration (octave) of added fractal noise.

Flow Rotation

When Noise type is “Flow”, this controls the rotation of the “swirl”, from 0 to 1. Because this parameter is fractional, you can’t just use $F to animate it, since all integral values will look the same, representing a complete revolution. Instead, try something like $FF / 100.

Distortion

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:

Stretch

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:

Droop

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.

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:

Blend

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.

Erosion

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.

Post-Process

Enable Minimum

Clamp the lower end of the generated noise values.

Minimum

When the checkbox is on, clamp values so they are never less than this value, after noise is applied. For vector attributes, the node applies this minimum to all components.

Enable Maximum

Clamp the higher end of the generated noise values.

Maximum

When the checkbox is on, clamp values so they are never greater than this value, after noise is applied. For vector attributes, the node applies this maximum to all components.

Make Vectors Unit Length

When the Attribute Type is Vector, turn this on to normalize the output values so they all have the same length (1).

Recompute Normals

Recomputes normals, if they exist.

Overview ¶

Tips and notes ¶

Parameters ¶

Geometry nodes