Houdini 20.0 Nodes Dynamics nodes

Gas Vortex Boost dynamics node

Applies a confinement force on specific bands of sampled energy.

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Since 12.0

The Gas Vortex Boost DOP applies confinement to a specific band of energy captured from the velocity field. This band can be amplified or weakened to pump energy into the velocity field at a certain frequency, or subtract energy from the velocity field at a certain frequency. Resulting in amplified curl movement or decreased angular motion (friction). This force is based on the Vortex Confinement microsolver but adds the control of selecting where to apply confinement. Imitating a band pass filter. Confinement is a force which amplifies existing vortices with the intent of undoing the diffusion that occurs during the diffusion stages of the fluid solver.

Multiple Vortex Boost microsolvers are combined to create the Gas Vortex Equalizer microsolver.


Swirl Size

Starting Frequency. A Swirl Size of 1 is the sample frequency associated with the first band, and is used to find the energy captured in 'swirls' measuring a width of 1. The 2nd band samples the energy captured in curls measuring a width of 0.5. The lower the frequency, the smaller the sampled energy becomes. Values lower then the actual voxel division size have no effect. They only add noise.


The amount to amplify the curl of a certain size with. The bands are normalized relative to each other. The calculated energy in the first band is the same as the energy in the last band. The actual boost value depends on the original velocity.


Applies a smooth clamping operation based on the band’s energy. The Target value determines up to what point the curl can be amplified. This is useful when running into unstable or noisy behavior.

Time Scale

Specifies a scale factor that relates DOP time to the simulation time for this microsolver. A value greater than one means the simulation time advances faster than the DOP time. A value less than one causes the simulation to appear to run in slow motion relative to the DOP time. Several expression functions such as doptime exist for converting from global times to simulation times and vice versa.


For all the other visualization options, refer to the Scalar Field Visualization and Vector Field Visualization node help.

Visualize Energy

Visualizes the energy associated with a band’s sample frequency. This is very useful for determining area of influence

Visualize Curl

Visualizes the direction and magnitude associated with a band’s sample frequency. This will be added to the velocity field specified.


Clear Temporary Fields

Zeros the temporary fields when finished to reduce memory usage.

Energy, Swirl Force and Curl Field

The name of the temporary fields to store intermediate steps needed in the calculation of vortex confinement. These will be created with a Gas Match Field so it does not need to exist ahead of time.

Velocity Field

Used for sampling information from, and apply force to.



Dynamics nodes