Using both horizontal and vertical planes in ARKit / RealityKit

Question

I’m having trouble with detecting both horizontal and vertical planes in ARKit. I have so far successfully been able to detect horizontal planes to some extent, but would like to integrate this with support for vertical planes as well.

My goal is to create an AR project that has a ball that can bounce off the floor and off walls. Without vertical plane detection, the ball bounces into the distance until it can no longer be seen.

What I have for horizontal plane detection is below.

public func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
    guard let planeAnchor = anchor as? ARPlaneAnchor else { return }
    let width = CGFloat(planeAnchor.extent.x)
    let height = CGFloat(planeAnchor.extent.z)
    let plane = SCNPlane(width: width, height: height)
    plane.materials.first?.diffuse.contents = UIColor.init(white: 1, alpha: 1)
    let planeNode = SCNNode(geometry: plane)
    let x = CGFloat(planeAnchor.center.x)
    let y = CGFloat(planeAnchor.center.y)
    let z = CGFloat(planeAnchor.center.z)
    planeNode.position = SCNVector3(x,y,z)
    planeNode.eulerAngles.x = -.pi / 2
    scene.rootNode.addChildNode(planeNode)
    let box = SCNBox(width: CGFloat(planeAnchor.extent.x), height: CGFloat(planeAnchor.extent.z), length: CGFloat(planeAnchor.extent.y), chamferRadius: 0)
    planeNode.physicsBody = SCNPhysicsBody(type: .static, shape: SCNPhysicsShape(geometry: box, options: nil))
}

How can I have both horizontal and vertical planes in an ARKit or RealityKit project?

Andy Jazz Andy Jazz · Accepted Answer · 2019-11-20T07:01:12

You can do it as usual, using the following code:

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

    let configuration = ARWorldTrackingConfiguration()
    configuration.planeDetection = [.horizontal, .vertical]
    arView.session.run(configuration)
}

planeDetection instance property is gettable and settable:

var planeDetection: ARWorldTrackingConfiguration.PlaneDetection { get set }

...and PlaneDetection struct conforms to OptionSet protocol which allows you to use just a single value or both values at the same time:

configuration.planeDetection = []
configuration.planeDetection = .vertical
configuration.planeDetection = [.horizontal, .vertical]

Then add renderer(_:didAdd:for:) instance method to your code that might look like this:

func renderer(_ renderer: SCNSceneRenderer,
             didAdd node: SCNNode,
              for anchor: ARAnchor) {

    guard let planeAnchor = anchor as? ARPlaneAnchor 
    else { return }

    let width = CGFloat(planeAnchor.extent.x)
    let height = CGFloat(planeAnchor.extent.z)
    let myPlane = SCNPlane(width: width, height: height)           

    if planeAnchor.alignment == .horizontal {
        myPlane.materials.first?.diffuse.contents = UIColor.semiOpaqueRed
    } else if planeAnchor.alignment == .vertical {
        myPlane.materials.first?.diffuse.contents = UIColor.semiOpaqueCyan
    }

    let planeNode = SCNNode(geometry: myPlane)
    let x = CGFloat(planeAnchor.center.x)
    let y = CGFloat(planeAnchor.center.y)
    let z = CGFloat(planeAnchor.center.z)

    planeNode.position = SCNVector3(x, y, z)
    planeNode.eulerAngles.x = -.pi / 2

    node.addChildNode(planeNode)
}

And, at last, add renderer(_:didUpdate:for:) instance method that might look like this:

func renderer(_ renderer: SCNSceneRenderer,
          didUpdate node: SCNNode,
              for anchor: ARAnchor) {

    guard let planeAnchor = anchor as? ARPlaneAnchor,
          let planeNode = node.childNodes.first,
          let myPlane = planeNode.geometry as? SCNPlane
    else { return }

    let width = CGFloat(planeAnchor.extent.x)
    let height = CGFloat(planeAnchor.extent.z)
    myPlane.width = width
    myPlane.height = height

    let x = CGFloat(planeAnchor.center.x)
    let y = CGFloat(planeAnchor.center.y)
    let z = CGFloat(planeAnchor.center.z)
    planeNode.position = SCNVector3(x, y, z)
}

Using both horizontal and vertical planes in ARKit / RealityKit

1 Answers