Swift ARKit How do you fully kill an ARSession?

Question

I have an ARSCNView running an ARSession. You can pause the session with session.pause() sure, but that still in effect, leaves the session running. I have tried deallocating the ARSCNView by removing it from its superview. The ARSCNView indeed deallocates but the ARSession is still running afterwards!! You can't assign nil to ARSession either. I can see the ARSessionDelegate's

func session(_ session: ARSession, didUpdate frame: ARFrame) 

is still being called!

How do you completely wipe the slate clean with ARKit once you have finished with it?

Is it even possible?

Answer 1

Officially, right now, you can't.

However, there is a work-around: you make the ARSCNView disposable.

On leaving AR, first pause the ARSession. Then deallocate the entire ARSCNView hierarchy & set ARSCNView to nil for good measure. Rebuild the entire ARSCNView hierarchy and start a new session whenever you need to go back to AR.

var ARview: ARSCNView?

func punchTheClown() {

    ARView?.session.pause()
    ARView?.removeFromSuperview()
    ARView = nil

}

Other non-AR areas of your app would typically be in a separate view hierarchy at the same sibling level as your ARSCNView. I look forward to Apple providing an actual stopSession() function, so we can all stop having to punchTheClown in the meantime.