ARFoundation iOS - Camera not always activating when ARSession begins

Hi,

I've noticed that sometimes when the ARSession begins the camera doesn't "activate" and the app just shows whatever background the unity camera is set to use, instead of the real world.

Is there an order in which components need to be turned on when starting an AR session? When this happens it seems like turning the ARSession component on and off solves the problem.

This happens randomly either when having everything setup on app startup, or when starting the session in code by turning on all the relevant components.

I thought I'd fixed it by adding a slight delay between starting the session and enabling the camera + background managers, but turns out it keeps happening from time to time.

Since there are a few components required to run an AR session, could it be a race condition between:
ARSession
ARInputManager
ARSessionOrigin
CameraManager
TrackedPoseDriver
ARCameraBackground

Any help appreciated, this never happened with the old ARKit plugin, seems to be an ARFoundation thing.

edit: Using Unity 2019.2.0f1 and ARFoundation 3.0.0 preview 2

 

Hi, this sounds exactly like something that I've been running. Did you ever manage fix this?

 

Hi, I seem to have the same problem a couple of years later. Do you remember how you resolved it? I don't really like the solution with the delay, but it works.