What does ParticleSystem.Stop do by default?

Stops emitting new particles. In-flight particles continue until their lifetime expires. This is StopEmitting behavior. If you want to clear immediately, pass StopEmittingAndClear.

Why do my particles persist after Stop?

Existing particles aren’t cleared by default Stop. For instant clear, use particles.Stop(true, ParticleSystemStopBehavior.StopEmittingAndClear) or call Clear() separately.

What about Sub-Emitters?

Sub-emitters tied to a parent are stopped recursively when withChildren = true (first argument of Stop). Set this true for compound particle systems — otherwise child emitters keep emitting.

Fix: Unity ParticleSystem Stop with Emitting Leak

Quick answer: Call particles.Stop(true, ParticleSystemStopBehavior.StopEmittingAndClear) for instant clear including sub-emitters. Default Stop only stops new emissions.

A fire effect’s emitter is stopped when the fire goes out. The visible flames persist for 2 seconds after stop. You wanted instant clear. The default Stop behavior keeps existing particles alive until their lifetimes expire.

Stop Behaviors

ParticleSystem.Stop has two parameters and two enum values:

withChildren (bool): apply to sub-emitters too.
stopBehavior (enum):
- StopEmitting: stop spawning new; existing live until natural death.
- StopEmittingAndClear: instant clear of all particles.

For Instant Disappearance

fireParticles.Stop(true, ParticleSystemStopBehavior.StopEmittingAndClear);

Stops emitting, clears all existing particles, and applies recursively to sub-emitters. The effect vanishes immediately.

For Natural Fadeout

fireParticles.Stop(true, ParticleSystemStopBehavior.StopEmitting);

Stops spawning new particles; existing particles complete their lifetimes. Used when you want the effect to fade naturally over its tail length.

Separate Clear

fireParticles.Clear(true);   // withChildren
fireParticles.Stop();

Manually clearing then stopping is equivalent to Stop with StopEmittingAndClear. Use when you need different conditions for each step.

Restart Pattern

For pooling: completely reset an emitter before re-use:

particles.Stop(true, ParticleSystemStopBehavior.StopEmittingAndClear);
particles.Play(true);   // withChildren

Cleans the system, starts fresh. Reliable across reuse cycles.

Verifying

Trigger Stop. With StopEmittingAndClear, the effect disappears within 1 frame. Without, existing particles continue until their lifetime expires. Capture both for comparison; pick the right behavior for your use case.

“Stop has two arguments. The second one matters: StopEmittingAndClear instead of the default StopEmitting.”

For pooled effects, always Stop(true, StopEmittingAndClear) on return-to-pool — eliminates leftover particle artifacts on next play.