Utsira

override func viewWillAppear(_ animated: Bool) {
	super.viewWillAppear(animated)
	startTracking()
}

private func startTracking() {
	sceneView.debugOptions = [ARSCNDebugOptions.showFeaturePoints]
	let configuration = ARWorldTrackingConfiguration()
	configuration.planeDetection = [.vertical, .horizontal]
	sceneView.session.run(configuration, options: [.resetTracking, .removeExistingAnchors])

Utsira

func renderer(_ renderer: SCNSceneRenderer, nodeFor anchor: ARAnchor) -> SCNNode? {
	guard let plane = anchor as? ARPlaneAnchor,
		let device = renderer.device,
		let geometry = ARSCNPlaneGeometry(device: device)
		else { return nil }
	geometry.update(from: plane.geometry)
	let maskMaterial = SCNMaterial()
	maskMaterial.colorBufferWriteMask = []
	geometry.materials = [maskMaterial]
	let node = SCNNode(geometry: geometry)

Utsira

func renderer(_ renderer: SCNSceneRenderer, didUpdate node: SCNNode, for anchor: ARAnchor) {
	guard let plane = anchor as? ARPlaneAnchor,
		let geometry = node.geometry as? ARSCNPlaneGeometry
		else { return }
	geometry.update(from: plane.geometry)
	node.boundingBox = planeBoundary(extent: plane.extent)
}

Utsira

private func planeBoundary(extent: float3) -> (min: SCNVector3, max: SCNVector3) {
	let radius = extent * 0.5
	return (min: SCNVector3(-radius), max: SCNVector3(radius))
}