Update all views while UISlider is being changed - sprite-kit

Question

Hello I have a SCNScene with a sprite kit overlay. I also have a subview that contains just a UISlider. The Slider controls the value of one of the SKLabel nodes in the sprite kit overlay. However when I am moving the slider the label does not update. It only updates once I touch outside of the slider. So I am guessing that the SCNScene and the overlay don't update while my touches are in the subview and only update once I touch back to the main view. How can I fix this?
Thanks!
My project is in swift, but if you only know objective-c ill still gratefully take your answer and translate on my own.
SceneKit Code:
class MyMarbleScene: UIViewController {
var scene: SCNScene!
var sceneView: SCNView!
var hud : MyMarbleSpriteKit!
var cameraNode: SCNNode!
override func viewDidLoad() {
super.viewDidLoad()
// create a new scene
scene = SCNScene()
sceneView = SCNView()
sceneView.frame = self.view.frame
sceneView.autoresizingMask = UIViewAutoresizing.allZeros
sceneView.scene = scene
sceneView.autoenablesDefaultLighting = false
sceneView.allowsCameraControl = false
sceneView.backgroundColor = UIColor.blackColor()
self.view = sceneView
cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
scene.rootNode.addChildNode(cameraNode)
cameraNode.position = SCNVector3(x: 0, y: 20, z: 60)
hud = MyMarbleSpriteKit(size: self.view.frame.size, game: self)
sceneView.overlaySKScene = hud
let frame = CGRectMake(10.0, self.view.frame.height*0.5, 180.0, 10.0)
let slider = UISlider(frame: frame)
slider.addTarget(self, action: "sliderValueChanged:", forControlEvents: UIControlEvents.ValueChanged)
slider.backgroundColor = UIColor.clearColor()
slider.minimumValue = 1.0
slider.maximumValue = 10.0
slider.continuous = true
slider.value = 5
self.view?.addSubview(slider)
}
func sliderValueChanged(sender: UISlider) {
var currentValue = Int(sender.value)
println("\(currentValue)")
self.hud.updateLabel(currentValue)
}
}
SpriteKit code
class MyMarbleSpriteKit: SKScene {
var myScene: MyMarbleScene!
var SensLabelTwo = SKLabelNode()
override func didMoveToView(view: SKView) {
}
init(size: CGSize, game:MyMarbleScene) {
super.init(size: size)
myScene = game
let SensLabel = SKLabelNode()
SensLabel.text = "Marble Sensitivity:"
SensLabel.fontName = "AvenirNext-HeavyIta"
SensLabel.fontSize = 40
SensLabel.fontColor = UIColor.whiteColor()
SensLabel.verticalAlignmentMode = SKLabelVerticalAlignmentMode.Top
SensLabel.position = CGPoint(x: 170, y: size.height-20)
self.addChild(SensLabel)
SensLabelTwo.text = "5"
SensLabelTwo.fontName = "AvenirNext-HeavyIta"
SensLabelTwo.fontSize = 60
SensLabelTwo.fontColor = UIColor.whiteColor()
SensLabelTwo.verticalAlignmentMode = SKLabelVerticalAlignmentMode.Top
SensLabelTwo.position = CGPoint(x: 100, y: size.height-80)
self.addChild(SensLabelTwo)
}
func updateLabel(text: Int){
println("helllo")
SensLabelTwo.text = String(format:"%i", text)
}
required init(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}

Answer 1

the 2D scene is not automatically refreshed when it's modified.
You will have to wait for the 3D scene to be redisplayed first. This happens when 3D animations or actions are running or when playing is set to YES. Alternatively, you can manually request a refresh with -[SCNView setNeedsDisplay].