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Question Configurable joint behaves differently after conversion from 2021 to 2023.

Discussion in 'Physics' started by koirat, Jan 29, 2024.

  1. koirat

    koirat

    Joined:
    Jul 7, 2012
    Posts:
    2,073
    On the picture below you can see a tree.
    Every branch of this tree is a physics body connected with configurable joints.
    I'm creating this joints runtime.

    In unity 2021 the tree was standing, on unity 2023 the tree is not - like there is not enough forces in joints motors.
    What was the change made to physics that is causing this issue ?

    upload_2024-1-29_18-47-17.png

    [edit]
    May it be related to this issue ?
    https://forum.unity.com/threads/2021-2022-inertia-tensor-behaviour.1501085/
    [/edit]
     
    Last edited: Jan 29, 2024
  2. Edy

    Edy

    Joined:
    Jun 3, 2010
    Posts:
    2,510
    As for the recent information on the linked issue, I'd check the Solver Type settings in your project's Physics settings.

    If you're using Temporal Gauss Seidel (TGS), then it's probably caused by that issue. The solution could be increasing the damping rate in the joints. It seems that recent improvements in TGS removed some implicit damping caused by the solver loosing energy in its calculations. Check out this specific post:

    https://forum.unity.com/threads/2021-2022-inertia-tensor-behaviour.1501085/#post-9610559

    If you're using Projected Gauss Seidel (PGS) then the physics behavior should be the same.
     
    koirat likes this.
  3. koirat

    koirat

    Joined:
    Jul 7, 2012
    Posts:
    2,073
    Yes I'm using TGS.
    I have played with it for a while but no satisfactory results after dampening or spring values increase.
    I will wait and see how the situation evolve.
     
    Edy likes this.