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Fixed in 2018.3.X



Found in


Issue ID




[iOS][Physics] Two MeshColliders pass through each other at certain angles on iOS only



With a specific mesh in the scene, when another mesh is moving towards it (standard Cube, Sphere or a custom mesh), instead of colliding, it passes through.

Steps to reproduce:
1) Open the latest attached project (
2) Build for iOS.
3) Run on a device.
- Notice the cube passing through the mesh
- The scene reloads every 3 seconds
4) As the cube is approaching the wall, touch the screen (this rotates the cube a bit)
- The cube doesn't pass through the mesh

The scene consists of a mesh (curved wall mesh) and a cube moving towards it with small velocity. Instead of colliding with the mesh, the cube goes right through it. This does not occur if the mesh or the cube is initially rotated slightly (the angle is not 0, 90, 180, etc.) or rotated in runtime.
This issue doesn't occur on the Editor and Android.

Note: the mesh has volume.

Workaround: uncheck "Enable PCM" in Physics settings.

Reproduced on:
5.6.0b6, 5.5.1p1

Did not reproduce:

Devices tested:
iPhone 7 iOS 10.3
iPad Mini 2 iOS 9.2.1
LG Nexus 5 Android 6.0

Comments (8)

  1. cozyurt_unity

    Jul 13, 2020 17:17

    kedi ve köpek mamaları kedi kumu çeşitleri

  2. sarebots2

    Feb 08, 2019 17:08

    Experienced the same issue in 2018.3, disabling PCM didn't do anything. Temporary solution was increasing default contact offset in physics settings

  3. LouisHong

    May 12, 2018 12:47

    Still reproducible

  4. richie-greene

    Feb 12, 2018 14:10

    To reproduce 2017.1.3:

    Add default cube to test track scene in Unity vehicle tools package
    Drive vehicle at cube
    Intermittantly, vehicle will drives through cube entirely, collide with cube and stop, or drive partially through cube and then react to overlapping colliders and jump

  5. richie-greene

    Feb 12, 2018 14:03

    Reproduced with standard vehicle setup against box & mesh collider

    Building to IOS 11

    Workaround appears to work. Need to do more thorough testing

  6. Uri_Popov

    Nov 13, 2017 14:49

    Reproduced on Unity 2017.2.0p1 and iOS 11.1.1.
    Workaround noted here worked.

  7. ditrytus

    Mar 13, 2017 19:00

  8. Snoop-Kakapo

    Mar 05, 2017 09:45

    reproduce Unity 5.5.x and iOS build
    did not reproduce 5.4.x and iOS build

    We have the same issue if rb drag value of box collider gameobject is higher than the default value.

    Test scene:
    - ground gameobject with static mesh collider
    - moving gameobject with box collider and rb/continues dynamic collision detection (if rb drag value is 0.5 it is OK, if rb drag value is 12, gameobject very often goes through a ground/mesh collider

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