ARKit Moving Horizontal Plane Visualization - ios

Question

I'm able to create a horizontal plane the moment I detect a flat surface, but I am wondering if there is a way to display it while moving around similarly to the feature point debugging option?
Essentially, I want the plane to move with you, not add on to the plane.

Answer 1

Assuming I have interpreted your question correctly, you are essentially asking how can I update the visualisation of a detected plane as it increases in size etc.
There are a number of different ways that this can be achieved, but in this instance I will provide an example using a subclass of SCNNode which will update as the plane increases.
class PlaneNode: SCNNode {
let DEFAULT_IMAGE: String = "defaultGrid"
let NAME: String = "PlaneNode"
var planeGeometry: SCNPlane
var planeAnchor: ARPlaneAnchor
var widthInfo: String!
var heightInfo: String!
var alignmentInfo: String!
//---------------
//MARK: LifeCycle
//---------------
/// Inititialization
///
/// - Parameters:
/// - anchor: ARPlaneAnchor
/// - node: SCNNode
/// - node: Bool
init(anchor: ARPlaneAnchor, node: SCNNode, image: Bool, identifier: Int, opacity: CGFloat = 0.25){
//1. Create The SCNPlaneGeometry
self.planeAnchor = anchor
self.planeGeometry = SCNPlane(width: CGFloat(anchor.extent.x), height: CGFloat(anchor.extent.z))
let planeNode = SCNNode(geometry: planeGeometry)
super.init()
//2. If The Image Bool Is True We Use The Default Image From The Assets Bundle
let planeMaterial = SCNMaterial()
if image{
planeMaterial.diffuse.contents = UIImage(named: DEFAULT_IMAGE)
}else{
planeMaterial.diffuse.contents = UIColor.cyan
}
//3. Set The Geometries Contents
self.planeGeometry.materials = [planeMaterial]
//4. Set The Position Of The PlaneNode
planeNode.simdPosition = float3(self.planeAnchor.center.x, 0, self.planeAnchor.center.z)
//5. Rotate It On It's XAxis
planeNode.eulerAngles.x = -.pi / 2
//6. Set The Opacity Of The Node
planeNode.opacity = opacity
//7. Add The PlaneNode
node.addChildNode(planeNode)
//8. Set The Nodes ID
node.name = "\(NAME) \(identifier)"
}
required init?(coder aDecoder: NSCoder) { fatalError("init(coder:) has not been implemented") }
/// Updates The Size Of The Plane As & When The ARPlaneAnchor Has Been Updated
///
/// - Parameter anchor: ARPlaneAnchor
func update(_ anchor: ARPlaneAnchor) {
self.planeAnchor = anchor
self.planeGeometry.width = CGFloat(anchor.extent.x)
self.planeGeometry.height = CGFloat(anchor.extent.z)
self.position = SCNVector3Make(anchor.center.x, 0.01, anchor.center.z)
}
}
Having created our subclass we then need to use it within our ViewController.
You will normally get more than one ARPlaneAnchor and would probably store these in a dictionary, however in this example we just assume there will be one.
As such we will create a variable which will reference our PlaneNode:
var planeNode:PlaneNode?
Then in the ARSCNViewDelegate we will create our PlaneNode like so:
func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
//1. Get The Current ARPlaneAnchor
guard let anchor = anchor as? ARPlaneAnchor else { return }
//2. Create The PlaneNode
if planeNode == nil{
planeNode = PlaneNode(anchor: anchor, node: node, image: true, identifier: 0, opacity: 1)
node.addChildNode(planeNode!)
planeNode?.name = String("Detected Plane")
}
}
Then all you need to do is track the updating of the PlaneNode so that the visualization keeps updating e.g:
func renderer(_ renderer: SCNSceneRenderer, didUpdate node: SCNNode, for anchor: ARAnchor) {
guard let anchor = anchor as? ARPlaneAnchor, let existingPlane = planeNode else { return }
existingPlane.update(anchor)
}