ARKit switch between ARWorldTrackingConfiguration and ARFaceTrackingConfiguration - Rear and Front Camera - ios

Question

In my project I want to switch between ARWorldTrackingConfiguration and ARFaceTrackingConfiguration.
I use two different types of view a ARSCNView to use the rear camera and a ARView to do the face tracking.
First I start the ARSCNView and after, if the user want, he can switch to face tracking
I start my view controller in this mode:
sceneView.delegate = self
sceneView.session.delegate = self
// Set up scene content.
setupCamera()
sceneView.scene.rootNode.addChildNode(focusSquare)
let configurationBack = ARWorldTrackingConfiguration(
configurationBack.isAutoFocusEnabled = true
configurationBack.planeDetection = [.horizontal, .vertical]
sceneView.session.run(configurationBack, options: [.resetTracking, .removeExistingAnchors])
And I load my Object (.scn)
When I want to switch to front camera I and pass to ARView I do this:
let configurationFront = ARFaceTrackingConfiguration()
// here I stop my ARSCNView session
self.sceneView.session.pause()
self.myArView = ARView.init(frame: self.sceneView.frame)
self.myArView!.session.run(configurationFront)
self.myArView!.session.delegate = self
self.view.insertSubview(self.myArView!, aboveSubview: self.sceneView)
And than I load my .rcproject
So my problem begin here, when I try to return to back camera and pass to ARWorldTracking again.
This is my method:
// remove my ARView with face tracking
self.myArView?.session.pause()
UIView.animate(withDuration: 0.2, animations: {
self.myArView?.alpha = 0
}) { (true) in
self.myArView?.removeFromSuperview()
self.myArView = nil
}
// here I restart the initial ARSCNView
let configurationBack = ARWorldTrackingConfiguration(
configurationBack.isAutoFocusEnabled = true
configurationBack.planeDetection = [.horizontal, .vertical]
session.run(configurationBack, options: [.resetTracking, .removeExistingAnchors])
When I switch to back camera, the sensor doesn't track the planes correctly.
How can I fix that, so how can I switch correctly between ARWorldTrackingConfiguration and ARFaceTrackingConfiguration?
Thanks in advance

Answer 1

Make sure to also remove all added nodes to the scene when you're pausing the session. Add below code after where you pause the session with self.sceneView.session.pause():
self.sceneView.scene.rootNode.enumerateChildNodes { (childNode, _) in
childNode.removeFromParentNode()
}