Most actions in Particle Flow operate on particles in either of two time frames: once, when the particle first enters the event, or on a continuous basis, potentially changing particle behavior at each integration step (that is, the whole time the particle is in the action’s event). Some actions can work only in one time frame, while others can work on an instantaneous or continuous basis, depending on their settings. The tables in this topic list each action with its time frame.
The operator is the basic element of the particle system: you combine operators into events to specify the particles' characteristics over a given period of time. Operators let you describe particle speed and direction, shape, appearance, and more.
Particle Flow includes the ability to generate particles from specific locations by “painting” particle generators, or seeds, on object surfaces. The toolset for doing so includes the Particle Paint helper and the Placement Paint operator.