Houdini 22.0 Nodes Copernicus nodes

Pyro Turbulence Copernicus node

Apply turbulence to a velocity VDB.

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Since 21.0

Note

Although COP Pyro is in COPs, you need DOP level permissions to use it. This means that COP Pyro is not available in Houdini Core, but only in Houdini FX, Houdini Apprentice, Houdini Indie, and Houdini Education.

This node applies a turbulent force to a velocity VDB.

Note

This turbulence differs from the one in the Pyro Solver SOP by a factor of about 12.

Parameters

Force

Operation

Controls how the force is combined with the incoming velocity field.

Set

Replaces the incoming velocities with the force values.

Force

Adds the force values to the incoming velocities.

Amplitude

Controls the overall strength of the force.

Amplitude Scale

Applies an anisotropic scale to the force.

Element Size

Controls the size of the noise elements at the base level of the noise.

Element Scale

Applies an anisotropic scale to the base-level noise element size.

Pulse Duration

The time, in seconds, required for the base level of the noise to fully change.

Attenuation

Controls the gradual loss of intensity.

Seed

Defines the initial noise offset.

Use Curl Noise

Uses curl noise instead of regular noise. Curl noise is divergence-free, so it remains relatively unchanged by pressure projection. It is best suited for introducing smooth motion, while non-curl noise is faster and better suited for adding energy.

Fractal

Max Octaves

Controls the number of turbulence levels applied relative to the initial Element Size.

Lacunarity

Controls the scale factor between successive turbulence octaves.

Roughness

Controls how much each octave contributes relative to the previous one. Values below 1 ensure that smaller features do not overwhelm larger features.

Mask by Threshold Field

Masks the effect of the force using the threshold field. Threshold fields are intended to produce sharp on/off transitions, but the range controls can be used to soften the transition.

Mask by Control Field

Masks the effect of the force using the control field. Control fields are typically used as masks and provide a smooth transition in the strength of the effect.

Mask along Axis

Masks the effect of the force along a specified axis.

This provides a convenient way to scale the effect over a world-space range without needing to construct VDB fields for masking.

Inputs

v

Vector VDB to use as the original velocities.

threshold

A Float or Vector VDB to use as a threshold field. If it is a Vector VDB, its length is used.

control

A Float or Vector VDB to use as a control field. If it is a Vector VDB, its length is used.

Outputs

v

The modified velocities after turbulent force is applied.

See also

Copernicus nodes