Houdini 21.0 Nodes Copernicus nodes

Pyro Turbulence Copernicus node

Apply turbulence to a velocity VDB.

On this page
Since 21.0

This operation 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

How to mix the force in with the incoming velocities.

Set

Replace the velocities with the force value.

Force

Add the force to the incoming velocities.

Amplitude

Global scale of the force.

Amplitude Scale

Anisotropic scale on the force.

Element Size

Size of the elements of the base level of noise.

Element Scale

Anisotropic scale on the base level noise element size.

Pulse Duration

Time in seconds for the base level of noise to fully change.

Attenuation

Defines the gradual loss of intensity.

Seed

Defines initial noise offset.

Use Curl Noise

Curl noise is divergent-free so will remain relatively unchanged by pressure projection. It is best for introducing smooth motion, while the non-curl is faster and useful for just adding energy.

Fractal

Max Octaves

Levels of turbulence to apply relative to the initial Element Size

Lacunarity

The scale factor between each octave of turbulence.

Roughness

Each octave is scaled by the roughness, values below one ensure the smaller features don’t overwhelm the larger features.

Mask by Threshold Field

Mask out the effect of the force by the threshold field. Threshold fields are intended to provide harsh on/off effects, but the range can be used to soften the transition.

Mask by Control Field

Mask out the effect of the force by the control field. Control fields are usually used the same way as masks, so represent a smooth engagement of the effect.

Mask along Axis

It is common for effects to be scaled along one particular axis. Rather than requiring the construction of VDBs to represent this; this allows the direct specification of the world space range over which the effect is to be scaled.

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