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[Solved]Particle System "Physics Module" is stripped - how to prevent without disabling stripping?

Discussion in 'Physics' started by bilalakil, Dec 27, 2019.

  1. bilalakil

    bilalakil

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    When running my game on device, I see the following warning in the debug log:

    > The ParticleSystem uses a gravityModifier, but the Physics Module is stripped, so using a default value of 9.81m/sec/sec for gravity. Disable stripping in Player Settings to fix this.
    >
    > (Filename: ./Modules/ParticleSystem/Modules/InitialModule.cpp Line: 58)

    I've already a solution in place for preventing other Unity classes from being stripped (different types of colliders). However, I don't know what "Physics Module" this is referring to, so I don't know how to solve the problem.

    - I don't want to disable stripping - it's a good thing. I just want to prevent this specific module from being stripped, which I usually do by specifically interacting with it in a startup scene (as I've done to solve the other problems).
    - I don't see any Physics module on a Particle System.
    - I tried including a particle system with all modules enabled in the startup scene, but the "Physics Module" is still being stripped.
    - I searched this error online and didn't find anything useful.

    How can I prevent this from being stripped, so my gravity modifications can work fine?
     
    bilalakil, Dec 27, 2019
    #1

  2. bilalakil

    bilalakil

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    Turns out that although this is a 2D game, and 2D physics is used everywhere, it seemed to be referring to the 3D physics module that's being stripped.

    I tried adding a RB/3D collider to my loading scene prevent a theoretical 3D physics module from being stripped, and now we're good!

    Interesting that I needed to include the entire 3D physics module to solve this problem in a 2D game... Would be great if that wasn't necessary!
     
    bilalakil, Dec 27, 2019
    #2

  3. MelvMay

    MelvMay

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    FYI: I forwarded this post to the particle devs for you.
     
    MelvMay, Dec 28, 2019
    #3
    richardkettlewell and bilalakil like this.

  4. richardkettlewell

    richardkettlewell

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    Hey, yeah the gravity setting in the main particle settings uses the physics module, in case a non-default gravity force is being used (I.e not 9.81)

    In the package manager, in the built-in packages list, is the physics module enabled?

    And, perhaps more importantly, does 2d physics have its own gravity modifier?
     
    Last edited: Dec 28, 2019
    richardkettlewell, Dec 28, 2019
    #4

  5. bilalakil

    bilalakil

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    @richardkettlewell Thanks for checking in!

    The built-in physics and physics2D packages are enabled.

    Looks like 2D has its own: https://docs.unity3d.com/ScriptReference/Physics2D-gravity.html

    I suppose there's no way to tell the particle system which physics system to use? It's got a mix of 2D/3D settings - would be useful to be able to select the specific mode or have a separate component(s) with only the relevant settings visible.
     
    bilalakil, Dec 30, 2019
    #5

  6. richardkettlewell

    richardkettlewell

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    Yeah you’re right. It’s an interesting problem - you really ought to be able to pick somehow. Right now a 2d system is still using the 3D system for gravity.

    I’ll add something to our roadmap to let you pick.

    Thanks!
     
    richardkettlewell, Dec 30, 2019
    #6

  7. kyuskoj

    kyuskoj

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    @richardkettlewell What should I add to link.xml to avoid this warning. I am on 2019.4

    edit: I found out.
    <type fullname="UnityEngine.Physics" preserve="all" />
     
    Last edited: Oct 4, 2020
    kyuskoj, Oct 4, 2020
    #7
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  8. tessellation

    tessellation

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    Hi @richardkettlewell, do you know if this was ever implemented?
     
    tessellation, Jul 3, 2021
    #8

  9. richardkettlewell

    richardkettlewell

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    Hey, no, unfortunately not. We stopped adding new stuff to the old particle system, in favour of committing resource to the Visual Effect Graph instead. But let me look at this again - something this small can still be doable.
     
    richardkettlewell, Jul 6, 2021
    #9

  10. richardkettlewell

    richardkettlewell

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    The ability to choose between 2D and 3D gravity will be added in Unity 2022.1.
    Thanks for the nudge on this!
     
    richardkettlewell, Jul 6, 2021
    #10
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  11. tessellation

    tessellation

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    tessellation, Mar 27, 2023
    #11

  12. richardkettlewell

    richardkettlewell

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    Sorry, I don't think so - we don't generally backport new features, in order to reduce the risk of breaking stuff.
     
    richardkettlewell, Mar 28, 2023
    #12

  13. tessellation

    tessellation

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    Understood, thanks for considering it.
     
    tessellation, Mar 28, 2023
    #13