Flow Update operator

The Flow Update operator allows you to update particle properties based on matching particles within another flow.

Source flow

  • Flow object: the tyFlow object whose particles will be referenced.

  • Reference frame offset: the frame offset that the input flow object will be evaluated at.

  • Simulation groups: controls which particle simulation groups will be read from the input flow object.

  • Channels: controls which particle data channels to copy from the input flow object’s particles.


  • Track Birth Flow IDs: when enabled, particles will be matched using birth IDs previously imported with a Birth Flow operator. When disabled, each particle’s own birth ID will be used to find matching particles in the reference flow.

If you are using Flow Update in combination with Birth Flow, you should keep “track Birth Flow IDs” enabled. If you are using Flow Update on its own in order to transfer properties from any arbitrary external flow or particle system, you should disable “track Birth Flow IDs”.

  • Index is ID: stores the tracking ID as the particle’s system index, rather than its explicit ID. Enable this setting if the interface returns invalid particle IDs.

  • Delete if not found: if a particle does not have a matching particle in the input flow object, it will be deleted.