ParticleSystem .Play()/.Stop() not working properly

When I use ParticleSystem.Stop() and then .Play() the particles start spawning 1-2 seconds after the call.
If I swap .Stop() with .Pause() then it works, but my particles need to be updated after pausing hence I`m using .Stop().

Start delay is 0.

Any Idea?

Does not work:

Code (CSharp):

1.         foreach (ParticleSystem p in particles)
2.         {
3.             // For debugging
4.             a = isDrifting && p.isPlaying;
5.  
6.             //Particles
7.             if (isDrifting && driftDir != 0 && p.isStopped)
8.             {
9.                 p.Play();
10.             }
11.             else if (!isDrifting && !p.isStopped)
12.             {
13.                 p.Stop();
14.             }
15.         }

Does work:

Code (CSharp):

1.         foreach (ParticleSystem p in particles)
2.         {
3.             //For debugging
4.             a = isDrifting && p.isPlaying;
5.  
6.             //Particles
7.             if (isDrifting && driftDir != 0 && p.isPaused)
8.             {
9.                 p.Play();
10.             }
11.             else if (!isDrifting && !p.isPaused)
12.             {
13.                 p.Pause();
14.             }
15.         }

 

When you stop the particle system you're resetting it to it's starting position.
It takes 1-2 seconds for the particle system to "warm up" due to the speed of your particles.

If you check "Prewarm" in the particle system settings, this warm-up period is skipped and the particles will always play from the warmed up point in time.

Is that what you're looking for?

 

First of all: thank you!
it definitley looks like it's prewarming but checking the "Prewarm" option didn't change anything.

Here is a video of the problem. You can see that it takes some time till the particle gizmo appears after the system was stopped. If i call .Play() before the gizmo appears nothing happens.

 

If you put some Debug.Log calls in the play part of your code, is it actually getting in there when you expect?

What determines "isDrifting" and "driftDir"?

If you put the particle system in the scene by itself and check play automatically, does it play as soon as the scene starts?

 

Thanks for the reply
I found out what the problem is
If you call .Stop() on a particle system you can only start it with .Play() again when all particles have despawned. Since I used a lifetime of 3 seconds I couldnt start the particle system again.
Do you by any chance know a way around this?

 

Oh, I see what you mean. The particles are still alive so you'll need to find a way to kill them or just change the "max particles" on your particle system to a higher number.

You can use ParticleSystem.Clear() to remove all particles.

I'd recommend increasing the max particles though if performance is not an issue.

Edit: There's also a "Stop and Clear" option when stopping the particle system:
https://docs.unity3d.com/ScriptReference/ParticleSystem.Stop.html

Code (CSharp):

1. system.Stop(true, ParticleSystemStopBehavior.StopEmittingAndClear);

 

My particle count is at 1000 so that's no issue.
Every particle has to be killed before the system can start again no matter how many you have.
I would like to have the old particles still around when i start the system again but it seems like i have to clear first :/

Thank you for your help!

 

That's really strange, I have never run into this problem and I just use start/stop

I stumbled upon this thread which might be of use. You can enable/disable emission on the particlesystem:

https://answers.unity.com/questions/1210223/particle-system-wont-restart-emitting-before-last.html

Good luck

 

I've been running into a similar issue and been banging my head. For some reason adding this check on calling Play caused them to start playing. I'm wondering if the isPlaying and isPaused properties aren't being properly set in some situations. You have virtually the same code but it might not hurt to give this a try. Seems silly but I didn't do this for the longest time because it "should" have worked by just calling *ParticleSystem.Play() but alas, it makes it work for me.

Code (CSharp):

1.             if (!particle.isPlaying)
2.             {
3.                 particle.Play();
4.             }

 

after 6 years you answered but this helped me thank you

 

This is the answer that helped me: http://answers.unity.com/answers/1401811/view.html

Code (CSharp):

1. ParticleSystem.EmissionModule em = particleSystem.emission;
2. em.enabled = false;

 

This solved the issue for mi, thanks for sharing!

 

Looks like the isPlaying method returns true while some particle are still active.
You need to use isEmitting

Code (CSharp):

1.  
2. if (!MyParticles.isEmitting)
3. {
4.     MyParticles.Play();
5. }
6.  

 

Cheers Isgar, this is the solution I needed!

 

Thank you. It saved me from being stuck for the next few hours.

 

I try to never start/stop particle systems and it works quite well for short arbitrary bursts of particles.

ParticleSystems (particlesystems): Do not use Play() / Stop() repeatedly. Instead, use Emit().

https://forum.unity.com/threads/can...i-want-and-where-i-want.1146047/#post-7358438