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