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Fixed

Fixed in 6000.0.48f1, 6000.1.0b15, 6000.2.0a9, future release

Votes

9

Found in

6000.0.33f1

6000.1.0b1

6000.2.0a1

Issue ID

UUM-91813

Regression

Yes

Joint Physics result in unexpected behaviors when used for articulated vehicles like buses or trucks

3D Physics

-

Reproduction steps:
1. Open the attached “IN-91978” project
2. Enter the Play Mode
3. Observe the “Mond08” GameObject in the Game View

Expected result: The articulated bus behaves as it would in real life, with the rear part pushing or pulling the front
Actual result: Rigidbodies attached by ConfigurableJoint fly uncontrollably, display movement which is erratic and unrealistic, or do not move at all

Reproducible with: 2023.3.0a19, 6000.0.33f1, 6000.1.0b1
Not reproducible with: 2021.3.45f1, 2022.3.55f1, 2022.3.0a18

Reproducible on: Windows 10, Ubuntu 22.04 (user)
Not reproducible on: No other environments tested

Note:
- Unity 2023.3, 6.0 and 6.1 streams result in different behaviors, but in contrast they all do not work as expected

  1. Resolution Note (fix version 6000.2.0a9):

    Fixed swap bodies behaviour on configurable joint to match the 22LTS behaviour. The swap bodies now don't fully swap the actors pose but swap the parent - child actors on the joint. This means that the auto configured anchor does not change when the bodies are swapped.

  2. Resolution Note (fix version 6000.1.0b15):

    Fixed swap bodies behaviour on configurable joint to match the 22LTS behaviour. The swap bodies now don't fully swap the actors pose but swap the parent - child actors on the joint. This means that the auto configured anchor does not change when the bodies are swapped.

  3. Resolution Note (fix version 6000.0.48f1):

    Fixed swap bodies behaviour on configurable joint to match the 22LTS behaviour. The swap bodies now don't fully swap the actors pose but swap the parent - child actors on the joint. This means that the auto configured anchor does not change when the bodies are swapped.

Comments (11)

  1. Marcos-Elias

    Jan 04, 2025 19:16

    A small update:
    On Unity 6.0.32f1 it seems that it works if I disable "Auto configure connected anchor" on the ConfigurableJoint component. I have not tested yet with runtime created vehicles, which is also essential since my project supports modding.

    But it still does not work on 6.1 alpha regardless of that setting. Anyway it should work always, like before.

    I am crazy with this problem, so sad waiting for so long for Unity 6 to receive this bad quality update with a very essential feature that worked for 10+ years.

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