Resolved ARMeshManager - Hierarchy not allowed when using prefabs

Hi,

There is a hierarchy check in ARMeshManager.cs to ensure it is a child of an ARSessionOrigin. That works fine unless your ARSessionOrigin is a prefab or part of a prefab. In that case you get this even with a valid hierarchy:


After looking into it a bit more, it looks like unity goes through ARMeshManager.OnValidate() and GetSessionOrigin() a few times when opening the prefab or pressing Play, but at one point the ARSessionOrigin game object shows activeInHierarchy = false, which makes GetSessionOrigin() return null and shows this beautiful popup.

I just upgraded the packages to 4.1.7 from 4.1.1 and this started happening.
Using Unity 2021.1.6f1 and 2020.1.16f1

To reproduce, load the ClassificationMeshes scene from the arfoundation samples repo, and make the ARSessionOrigin object a prefab. You'll get the popup 2-3- times in a row.

Is there a way around this besides not using prefabs?

Thanks!

 

Hi,

I ran into a similar problem and fixed it by upgrading to ARFoundation 4.2.0

Hope it helps!

 

Ah thank you!
Glad they fixed it in 4.2