True seamless ParticleSystem looping

Unity Engine
1

Hello,
Is there a working way to achieve seamless looped particles with PS? I mean like for static particles that should keep their positions between simulations of the particle system.

I HAVE ALREADY TRIED:

  • turning off auto random seed
  • resimulating/clearin/stoping&playing when simulation time reaches its end.

This seems a serious issue to me. I am using U 5.4.3

Best!

2

In scripting, you can set your particleSystem.randomSeed. I know the name is deceiving, but if you set that value to the same number, it will simulate the same way each time.

A particle system always starts with a random seed. Setting “autoRandomSeed” to true simply disables it from getting a new random seed each time Play() is called.

3

Thanks, but that does not work at all, as I’ve written, I’ve already tried that.

4

Can you provide an example of what you are trying to achieve? Maybe a project file?

5

We have an issue similar to this.
Particle System is Looped, but not Prewarmed (Smoke rising slowly from a chimney)

Start ParticleSystem, save time to effectTime.
Move Camera far away → Stop particle System
Move Camera Back → ParticleSystem.Play and set ParticleSystem.time to Time.time - effectTime
Particle System starts from the beginning (because it’s Looped?) instead of at Time.time - effectTime.

6

Sounds like you want to use Simulate, not time. https://docs.unity3d.com/ScriptReference/ParticleSystem.Simulate.html
Record the time, call stop and use Simulate with that time to resume it.

1 Like
7

Thanks a lot! That does the trick, my code snippet for anyone else trying to do it

var time = Time.time - chimneyStartTime;
chimneyEffect.Simulate(time,false);
chimneyEffect.Play();

Any idea how efficient the Simulate function is? For example if I have the effect running for 10 min and want to restore it, will it be costly to call Simulate with a high t? The particle system duration is 8 sec looped with particle lifetime of 10 sec. Then again I can probably just consider any t higher 10 as 10. It will not be a perfect restore but not noticeable in my case.

1 Like
8

It could be quite costly if its a none procedural system. https://blogs.unity3d.com/2016/12/20/unitytips-particlesystem-performance-culling/

1 Like
9

Thanks guys! Will try that approach!