# Can't rewind a ParticleSystem. Bug?
**URL:** https://discussions.unity.com/t/cant-rewind-a-particlesystem-bug/474442
**Category:** Visual Effects
**Created:** [April 23, 2012, 11:18am UTC](https://discussions.unity.com/t/cant-rewind-a-particlesystem-bug/474442 "2012-04-23T11:18:26Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@anon20000101](https://discussions.unity.com/u/anon20000101)
#### Post date: [April 23, 2012, 11:18am UTC](https://discussions.unity.com/t/cant-rewind-a-particlesystem-bug/474442/1 "2012-04-23T11:18:26Z")
In my code I need to rewind a Shuriken ParticleSystem, just like I can rewind it in the Editor by dragging Playback Time.
The script reference says this is possible by setting the time property, but it doesn’t seem to work.
There is more information and sample code on the question I submitted here: [Rewind particle system (shuriken) - Questions & Answers - Unity Discussions](http://answers.unity3d.com/questions/243231/rewind-particle-system-shuriken.html)
Is this a bug? Did anyone ever set the time property and see it affect anything?
---
### Author:  [@anon\_90285639](https://discussions.unity.com/u/anon_90285639)
#### Post date: [April 23, 2012, 12:26pm UTC](https://discussions.unity.com/t/cant-rewind-a-particlesystem-bug/474442/2 "2012-04-23T12:26:29Z")
> [@system](#):
>
> In my code I need to rewind a Shuriken ParticleSystem, just like I can rewind it in the Editor by dragging Playback Time.
>
> The script reference says this is possible by setting the time property, but it doesn’t seem to work.
>
> There is more information and sample code on the question I submitted here: [http://answers.unity3d.com/questions/243231/rewind-particle-system-shuriken.html](http://answers.unity3d.com/questions/243231/rewind-particle-system-shuriken.html)
>
> Is this a bug? Did anyone ever set the time property and see it affect anything?
Hi!
The .time property only affects the emitter time. It does nothing to affect already existing particles. the way this can be used is if you have curves set up for start energy, start speed etc, then you can control the time of the emitter.
If you want to affect already emitted particles you have to use Simulate(). Unfortunately there is a bug that makes this quite broken, but if you Stop(), Clear() and Simulate(time) on every update, you should get something. This is fixed and is to be released in a future version. Additionally, this operation will be much faster than it currently is in most cases.
---
### Author:  [@dansav](https://discussions.unity.com/u/dansav)
#### Post date: [January 22, 2013, 10:11am UTC](https://discussions.unity.com/t/cant-rewind-a-particlesystem-bug/474442/3 "2013-01-22T10:11:37Z")
Was this ever fixed. I am trying to manually simulate the Shuriken softsnow particlesystem in the update loop using stop,clear and Simulate(t)
where t counts slowly = .01, .02,.03…
All I see is the snow jumping around randomly instead of falling slowly every frame.
Is there a fix available?
---
### Author:  [@Gamgie](https://discussions.unity.com/u/Gamgie)
#### Post date: [February 5, 2015, 2:13pm UTC](https://discussions.unity.com/t/cant-rewind-a-particlesystem-bug/474442/4 "2015-02-05T14:13:16Z")
Hello !
I have the same bug. It is said to be “This is fixed and is to be released in a future version”.
Is this still bugged or there is now another way to do it ?
Thank you !
---
### Author:  [@Gamgie](https://discussions.unity.com/u/Gamgie)
#### Post date: [February 5, 2015, 4:43pm UTC](https://discussions.unity.com/t/cant-rewind-a-particlesystem-bug/474442/5 "2015-02-05T16:43:19Z")
I can actually go backward if you do something like this in the update loop (with a randomSeed fixed) :
```csharp
float playbackTime = particleSystem.time;
particleSystem.Clear();
particleSystem.Simulate(playbackTime - Time.deltaTime);
particleSystem.Play();
```
It works well. But it begins to fail reaching a mystery time (for me it is after ~4.7s). The Simulate function seems to go to the same result for every time after that limit.
Is this a bug ? (or maybe I am doing something wrong).
---
### Author:  [@pet1100](https://discussions.unity.com/u/pet1100)
#### Post date: [March 21, 2017, 12:57pm UTC](https://discussions.unity.com/t/cant-rewind-a-particlesystem-bug/474442/6 "2017-03-21T12:57:42Z")
What gamgie said works perfectly. On a few extra condition.
Simulation speed is set to 1. (It hasn’t seemed to work with anything else, but there might be a fix I haven’t found/seen)
Particlesystem has to be stopped before setting a seed. (Always!)
particleSystem.time only give the current time of how far it is in the loop.
For a full rewind you need something to check how many cycles it have gone through.
And then multiply that with particleSystem.duration.
---
### Author:  [@JDatUnity](https://discussions.unity.com/u/JDatUnity)
#### Post date: [May 15, 2017, 12:20pm UTC](https://discussions.unity.com/t/cant-rewind-a-particlesystem-bug/474442/7 "2017-05-15T12:20:19Z")
> [@pet1100](#):
>
> What gamgie said works perfectly. On a few extra condition.
> Simulation speed is set to 1. (It hasn’t seemed to work with anything else, but there might be a fix I haven’t found/seen)
> Particlesystem has to be stopped before setting a seed. (Always!)
>
> particleSystem.time only give the current time of how far it is in the loop.
> For a full rewind you need something to check how many cycles it have gone through.
> And then multiply that with particleSystem.duration.
Could you perhaps elaborate? multiply what with what?