VDB Force operator

The VDB Force operator allows you to apply forces from VDB voxels to particles.

This operator derives forces from VDB data directly inside the flow. If you want to use forces from a VDB setup in another flow, for the time being you will have to export the VDB data of that other flow to a .vdb file and bring it into the current flow using a supported container (PhoenixFD or FumeFX container) and a Fluid Force operator.


Velocity grid

  • Grid name: the name of the source velocity grid.

Velocity Magnitude

These controls affect the overall magnitude of VDB forces applied to particle velocities.

  • Add/Blend/Replace: controls how forces computed by the operator will affect existing particle velocities.

  • Influence %: controls how much influence VDB forces will have on particle velocities.

  • Variation %: the per-particle percentage of variation to apply.

Velocity Direction

These controls affect the overall direction of VDB forces applied to particle velocities.

  • Add/Blend/Replace: controls how forces computed by the operator will affect existing particle velocities.

  • Influence %: controls how much influence VDB forces will have on particle velocities.

  • Variation %: the per-particle percentage of variation to apply.

Influence

  • X/Y/Z: controls which axis the forces will affect.

  • Simulate substeps: forces will be interpolated in a way that simulates the addition of forces at smaller simulation substeps.

Relative to property

The relative property multiplier will adjust values based on the ratio between the value of a particle property and the specified threshold value.

  • Property type: the particle property to which the threshold value will be compared.

  • Threshold: the target value to which the selected property value of a particle will be compared.

  • Min multiplier: the minimum value of the resulting multiplier.

  • Max multiplier: the maximum value of the resulting multiplier.

  • Exponent: the exponent to which the ratio between the particle property and the selected property will be raised.


Uniqueness

  • Seed: the seed value for all varied parameters.