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How do you rotate the spawn position of a particle system?

Discussion in 'Visual Effect Graph' started by Stacklucker, Feb 28, 2020.

  1. Stacklucker

    Stacklucker

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    When I initialize my particle in the VFX Graph, I can freely choose the spawn position and spawn shape, but what about rotation?

    Let's say I want to initialize my particles on the surface of a circle. Is there anyway to rotate the whole circle? I don't want my particles to spawn parallel to the ground level, but in specific rotational angles.

    Thanks for any help in advance.
     
    hipinds likes this.
  2. VladVNeykov

    VladVNeykov

    Unity Technologies

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    Hi @Stacklucker ,
    You can transform the positions and re-assign them to the graph. Something like this:
    upload_2020-2-28_17-5-14.png

    Hope this helps!
     
  3. Kikimacia

    Kikimacia

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    @VladVNeykov Oh man, I didn't even come on the forum for this but you made my day, I've been looking for this for 2 weeks now ! Thanks !
     
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  4. Stacklucker

    Stacklucker

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    @VladVNeykov sorry for my late response, but thank you so much for your detailed response. It worked!
     
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  5. cAyouMontreal

    cAyouMontreal

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    The thing is that you can also rotate the emitter and it will work, unless you are in world space, then you will have no choice but rotating yourself the emitter, which is a bit annoying, specially because the gizmo is then wrong (showing the false orientation). It would be great to have a rotation option (as well as offset and scaling, all non uniform) like in Shuriken.

    So right now in vfxgraph, if you want world based particle emission but also want to adapt the rotation of the emitter based on its parent (let's say a exhaust pipe from a car), you can't do it (good luck trying to find the correct rotation).
     
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  6. ESludden

    ESludden

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    @cAyouMontreal Yes, It would be useful to have a simple way to choose 'Simulate in worldspace' for the whole particle effect.

    Shuriken has this option as a dropdown menu item in its 'Simulation Space' attribute. Are there any plans to make this feature available in VFX Graph?

    I'm keen to have a worldpsace simulation so that I can take advantage of the performance of VFX Graph when my particle emitter moves and rotates its Transform in the game world.
     
  7. AidenEcho

    AidenEcho

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    Thanks to all guys. I tried to create a VFX and I used the "Position (Circle)" node, however the "Position (Circle)" node can't be rotated, so I rotated the VFX and used the Transform node to convert the position that I passed from parameters.
     
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  8. pjbaron

    pjbaron

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    The solution above worked perfectly for my simple case (I needed a hemisphere emitter flat on the ground, the default arc slices it vertically).
    I believe you can use world space rotations by exposing the Transform (Position) as a Property and setting it to match your (e.g.) exhaust pipe.
    Apologies if I get this wrong, but I think that what we're doing here is directly applying the transform to every particle as it is created and before it appears in the world, which makes this technique incredibly powerful (you can do anything to your emitters).
    My only criticism is that it's entirely obscure, there's no way I would have thought this might work if I hadn't found this thread.
    upload_2020-6-8_17-30-10.png
     

    Attached Files:

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  9. ctedin187

    ctedin187

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    Yay! I'm giving this a try. I asked in another part of the forum, but thought I'd stumble across it.
     
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  10. VladVNeykov

    VladVNeykov

    Unity Technologies

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    Exactly!

    Completely agree; we are aware that this is not very discoverable, and are planning on addressing it at the shape block level itself.
     
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  11. surits14

    surits14

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    Last edited: Jun 26, 2020
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  12. laurentlavigne

    laurentlavigne

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    Have you?
     

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  13. VladVNeykov

    VladVNeykov

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    There's a PR in progress at the moment addressing this.
     
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  14. koirat

    koirat

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    In some situations instead of full fledged rotation 90 deg you can just swap y<->z position components.
     
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  15. dnlbschff

    dnlbschff

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    It would be cool, if the shape Gizmo for the attached GameObject would be rotated with the shape block transform then as well.
     
  16. FlightOfOne

    FlightOfOne

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    I have been trying to figure this out for several days now.

    How do I do the same without the circle. I want to set the local rotation of the particle to x=90 while the particle system is in world space. Using angle (x=90) works as long as the system is in local space but when I switch to world space then it sets the world rotation to 90.

    Is there a block like chance space for angles?
     
    Last edited: May 21, 2021
  17. iDerp69

    iDerp69

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    @VladVNeykov I have been struggling with this for days... consulting help on the official Unity VFX Discord channel and nothing we've tried was able to get my VFX to work the way I'm intending. I'm trying to make action/speed lines for my vehicle-based game... simple speed trails that whiz by you as you drive fast. You would expect these to come from a torus shape in front of the vehicle in a heads/trails system, but I cannot get the torus to rotate. If there was a way to rotate the emitter directly on the Set Position Torus node, that would be extraordinarily helpful in making VFX graph a bit more beginner friendly. I am not the only one who is struggling with this as someone else was having essentially the same issue in that Discord at the same time.
     
  18. homemacai

    homemacai

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    So there is no way to rotate the emitters when suing World Space?
     
    Last edited: May 21, 2021
  19. mbach

    mbach

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    I am also struggling with this. The fact that emitters do not rotate when the system is in world space mode is very confusing and I don't know how to work around it. Please fix this, Unity. The trick that was suggested only works for systems in local space.
     
  20. VladVNeykov

    VladVNeykov

    Unity Technologies

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    Hi all,
    A quick update, in Unity 2021.2 we have now embedded transforms in the various shape blocks and operators, allowing you to easily move, rotate, or even scale shapes. Hope this makes things easier now! :)
     

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