swift - Creating a subclass of a SCNNode -

i'm loading node .dae file following code:

func newnode() -> scnnode { var node = scnnode() let scene = scnscene(named: "circle.dae") var nodearray = scene!.rootnode.childnodes  childnode in nodearray {     node.addchildnode(childnode as! scnnode)     } return node } 

i add properties , methods specific node when load in scene gets random color can modify whenever want. had done similar subclass of scnsphere (which geometry , not node, though) using:

let numberofcolors: uint32 = 4  enum ellipsoidcolor: int, printable { case red = 0, blue, green, white  var ellipsoidname: string {     switch self {     case .red:         return "red"     case .blue:         return "blue"     case .green:         return "green"     case .white:         return "white"     } }  var description: string {     return self.ellipsoidname }  static func random() -> ellipsoidcolor {     return ellipsoidcolor(rawvalue: int(arc4random_uniform(numberofcolors - 1)))!     } }   class ellipsoid: scnnode {  func setmaterialcolor(ellipsoidcolor: ellipsoidcolor) {     let color: uicolor      switch ellipsoidcolor {     case .red:         color = uicolor.redcolor()     case .blue:         color = uicolor.bluecolor()     case .green:         color = uicolor.greencolor()     case .white:         color = uicolor.whitecolor()     }      self.geometry?.firstmaterial!.diffuse.contents = color }  var color : ellipsoidcolor {     didset {         self.setmaterialcolor(color)     } }  init(color: ellipsoidcolor) {     self.color = color     super.init()     self.setmaterialcolor(color)     }  required init(coder adecoder: nscoder) {     fatalerror("init(coder:) has not been implemented")     } } 

how can "link" subclass node obtain using newnode() ? naively thought using

let ellipsoid = newnode() as! ellipsoid 

would work, doesn't. time , help.

well, code cannot work.

in newnode create scnnode:

func newnode() -> scnnode {    var node = scnnode()    //...    return node } 

and later on tell compiler scnnode ellipsoid

let ellipsoid = newnode() as! ellipsoid 

but isn't! it’s scnnode. of course program crash.

if want ellipsoid create one:

func newellipsoid() -> ellipsoid {    var node = ellipsoid()    //...    return node } 

(or wherever need create it)