ARSession.swift

//In our viewWillAppear configure the session to run with these settings
override func viewWillAppear(_ animated: Bool) {
  //Standard tracking configuration
  let configuration = ARWorldTrackingConfiguration()
  //We want to detect all horizontal planes (i.e. the floor)
  configuration.planeDetection = .horizontal
  //Set the delegate to be self so we can be updated when relevant things happen
  session.delegate = self
  //Run the session using this configuration (no options for this) 
  session.run(configuration, options: [])
  //Note: It is possible to run the session so that you can see the feature points being created by ARKit. 
}