I have a SCNPlane that is added to the scene when a sufficient area is detected for a horizontal surface. The plane appears to be placed in a correct spot, according to the floor/table it's being placed on. The problem is when I drop a SCNNode(this has been consistent whether it was a box, pyramid, 3D-model, etc.) onto the plane, it will eventually find a spot to land and 99% start jiggling all crazy. Very few times has it just landed and not moved at all. I also think this may be cause by the node being dropped and landing slightly below the plane surface. It is not "on top" neither "below" the plane. Maybe the node is freaking out because it's kind of teetering between both levels?
Here is a video of what's going on, you can see at the beginning that the box is below and above the plane and the orange box does stop when it collides with the dark blue box, but does go back to its jiggling ways when the green box collides with it at the end:
The code is here on github
I will also show some of the relevant parts embedded in code:
I just create a Plane class to add to the scene when I need to
class Plane: SCNNode {
var anchor :ARPlaneAnchor
var planeGeometry :SCNPlane!
init(anchor :ARPlaneAnchor) {
self.anchor = anchor
super.init()
setup()
}
func update(anchor: ARPlaneAnchor) {
self.planeGeometry.width = CGFloat(anchor.extent.x)
self.planeGeometry.height = CGFloat(anchor.extent.z)
self.position = SCNVector3Make(anchor.center.x, 0, anchor.center.z)
let planeNode = self.childNodes.first!
planeNode.physicsBody = SCNPhysicsBody(type: .static, shape: SCNPhysicsShape(geometry: self.planeGeometry, options: nil))
}
private func setup() {
//plane dimensions
self.planeGeometry = SCNPlane(width: CGFloat(self.anchor.extent.x), height: CGFloat(self.anchor.extent.z))
//plane material
let material = SCNMaterial()
material.diffuse.contents = UIImage(named: "tronGrid.png")
self.planeGeometry.materials = [material]
//plane geometry and physics
let planeNode = SCNNode(geometry: self.planeGeometry)
planeNode.physicsBody = SCNPhysicsBody(type: .static, shape: SCNPhysicsShape(geometry: self.planeGeometry, options: nil))
planeNode.physicsBody?.categoryBitMask = BodyType.plane.rawValue
planeNode.position = SCNVector3Make(anchor.center.x, 0, anchor.center.z)
planeNode.transform = SCNMatrix4MakeRotation(Float(-Double.pi / 2.0), 1, 0, 0)
//add plane node
self.addChildNode(planeNode)
}
This is the ViewController
enum BodyType: Int {
case box = 1
case pyramid = 2
case plane = 3
}
class ViewController: UIViewController, ARSCNViewDelegate, SCNPhysicsContactDelegate {
//outlets
@IBOutlet var sceneView: ARSCNView!
//globals
var planes = [Plane]()
var boxes = [SCNNode]()
//life cycle
override func viewDidLoad() {
super.viewDidLoad()
//set sceneView's frame
self.sceneView = ARSCNView(frame: self.view.frame)
//add debugging option for sceneView (show x, y , z coords)
self.sceneView.debugOptions = [ARSCNDebugOptions.showFeaturePoints, ARSCNDebugOptions.showWorldOrigin]
//give lighting to the scene
self.sceneView.autoenablesDefaultLighting = true
//add subview to scene
self.view.addSubview(self.sceneView)
// Set the view's delegate
sceneView.delegate = self
//subscribe to physics contact delegate
self.sceneView.scene.physicsWorld.contactDelegate = self
//show statistics such as fps and timing information
sceneView.showsStatistics = true
//create new scene
let scene = SCNScene()
//set scene to view
sceneView.scene = scene
//setup recognizer to add scooter to scene
let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(tapped))
sceneView.addGestureRecognizer(tapGestureRecognizer)
}
//MARK: helper funcs
@objc func tapped(recognizer: UIGestureRecognizer) {
let scnView = recognizer.view as! ARSCNView
let touchLocation = recognizer.location(in: scnView)
let touch = scnView.hitTest(touchLocation, types: .existingPlaneUsingExtent)
//take action if user touches box
if !touch.isEmpty {
guard let hitResult = touch.first else { return }
addBox(hitResult: hitResult)
}
}
private func addBox(hitResult: ARHitTestResult) {
let boxGeometry = SCNBox(width: 0.1,
height: 0.1,
length: 0.1,
chamferRadius: 0)
let material = SCNMaterial()
material.diffuse.contents = UIColor(red: .random(),
green: .random(),
blue: .random(),
alpha: 1.0)
boxGeometry.materials = [material]
let boxNode = SCNNode(geometry: boxGeometry)
//adding physics body, a box already has a shape, so nil is fine
boxNode.physicsBody = SCNPhysicsBody(type: .dynamic, shape: nil)
//set bitMask on boxNode, enabling objects with diff categoryBitMasks to collide w/ each other
boxNode.physicsBody?.categoryBitMask = BodyType.plane.rawValue | BodyType.box.rawValue
boxNode.position = SCNVector3(hitResult.worldTransform.columns.3.x,
hitResult.worldTransform.columns.3.y + 0.3,
hitResult.worldTransform.columns.3.z)
self.sceneView.scene.rootNode.addChildNode(boxNode)
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
let configuration = ARWorldTrackingConfiguration()
configuration.planeDetection = .horizontal
//track objects in ARWorld and start session
sceneView.session.run(configuration)
}
//MARK: - ARSCNViewDelegate
func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
//if no anchor found, don't render anything!
if !(anchor is ARPlaneAnchor) {
return
}
DispatchQueue.main.async {
//add plane to scene
let plane = Plane(anchor: anchor as! ARPlaneAnchor)
self.planes.append(plane)
node.addChildNode(plane)
//add initial scene object
let pyramidGeometry = SCNPyramid(width: CGFloat(plane.planeGeometry.width / 8), height: plane.planeGeometry.height / 8, length: plane.planeGeometry.height / 8)
pyramidGeometry.firstMaterial?.diffuse.contents = UIColor.white
let pyramidNode = SCNNode(geometry: pyramidGeometry)
pyramidNode.name = "pyramid"
pyramidNode.physicsBody = SCNPhysicsBody(type: .dynamic, shape: nil)
pyramidNode.physicsBody?.categoryBitMask = BodyType.pyramid.rawValue | BodyType.plane.rawValue
pyramidNode.physicsBody?.contactTestBitMask = BodyType.box.rawValue
pyramidNode.position = SCNVector3(-(plane.planeGeometry.width) / 3, 0, plane.planeGeometry.height / 3)
node.addChildNode(pyramidNode)
}
}
func renderer(_ renderer: SCNSceneRenderer, didUpdate node: SCNNode, for anchor: ARAnchor) {
let plane = self.planes.filter {
plane in return plane.anchor.identifier == anchor.identifier
}.first
if plane == nil {
return
}
plane?.update(anchor: anchor as! ARPlaneAnchor)
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
//pause session
sceneView.session.pause()
}
}
