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Question Spawn particles over time?

Discussion in 'Visual Effect Graph' started by Duncano, Feb 12, 2022.

  1. Duncano

    Duncano

    Joined:
    Feb 2, 2017
    Posts:
    3
    Really struggling to get particles to spawn for a set period of time, and then stop spawning.

    Essentially I want them to spawn for 1 second only.

    Any help massively appreciated...i would have thought this would be a common requirement for any particle system.

    Got excited when i found the 'set spawn time' node, but bummed out, when i realized there was no input field. thanks.
     
    Duncano, Feb 12, 2022
    #1

  2. koirat

    koirat

    Joined:
    Jul 7, 2012
    Posts:
    2,009
    You can control it from outside by stopping VFX by script, after one second passed.

    There is probably a second way, implementing your own spawn block (VFXSpawnerCallback), I tried to find some info on how to use it but could not.

    If you find something please share.
     
    koirat, Feb 14, 2022
    #2

  3. JulienF_Unity

    JulienF_Unity

    Unity Technologies

    Joined:
    Dec 17, 2015
    Posts:
    306
    Hi. The best way to do it would be to use the loop system in spawner contexts. Basically set you spawn context to run for 1 second and then stop (so 1 loop of 1 second). This can be set from the spawn context inspector.

    upload_2022-2-14_10-33-31.png
     
    JulienF_Unity, Feb 14, 2022
    #3
    Hzzzzzppl, a101012432, Duncano and 2 others like this.

  4. Duncano

    Duncano

    Joined:
    Feb 2, 2017
    Posts:
    3
    Thanks, i stumbled across the above solution on a different thread, its a really simple and nice way of handling it...it makes total sense. I am surprised its not more widely documented, i have been searching ' spawn time'...and the solutions that came back where mostly script based. I suppose the language / ui im used to is from 3D packages, when you generally set a start and end frame for spawning....so i was probably looking too hard for something similar. Loop duration and loop count is brill, and exactly what i need. thanks again!
     
    Duncano, Feb 14, 2022
    #4

  5. koirat

    koirat

    Joined:
    Jul 7, 2012
    Posts:
    2,009
    Is there some kind of event signaled when the VFX finished spawning and there are no more particles ?
    I would like to use this event for destruction of prefab or signaling other operations.
     
    koirat, Feb 14, 2022
    #5

  6. JulienF_Unity

    JulienF_Unity

    Unity Technologies

    Joined:
    Dec 17, 2015
    Posts:
    306
    Doc is here: https://docs.unity3d.com/Packages/com.unity.visualeffectgraph@10.8/manual/Context-Spawn.html

    You can check the sleeping state of a given system using https://docs.unity3d.com/ScriptReference/VFX.VisualEffect.GetParticleSystemInfo.html
    From 2021.2 onwards, we added a method directly in VisualEffect API https://docs.unity3d.com/2021.2/Doc...rence/VFX.VisualEffect.HasAnySystemAwake.html
    Note that sleep state won't work yet for some experimental features like strips or GPU events.
     
    JulienF_Unity, Feb 14, 2022
    #6
    koirat likes this.

  7. jitterware

    jitterware

    Joined:
    Mar 31, 2018
    Posts:
    4
    Cheers! I was searching for over an hour for this solution! Works perfect!
     
    jitterware, Aug 31, 2023
    #7