Animated 3D models using ARKit. Swift - swift

Question

I added purchased 3D zombie model and I want to add it multiple times so there is a group of zombies chasing the player (his camera). The DAE file (zombie) I have has couple of animations (attack, walk, run and so on). I added a couple of these zombie models and they all appear on the positions I wanted them to appear (previously determined coordinates stored in zombies array)
When they appear on the screen they do all the animations as it is presented in DAE file.
And now my question: Is it possible to add this DAE zombie model but display it in a specified frame? For example 2-122? My code so far (I deleted what was unnecessary)
import UIKit
import CoreLocation
import SceneKit
import ARKit
#available(iOS 11.0, *)
class VRViewController: UIViewController, CLLocationManagerDelegate
{
/* VARIABLES */
var number:Int = 10
var speed:Int = 4
var zombies = [[AnyObject]]()
var timer = Timer()
var nodes = [SCNNode]()
let configuration = ARWorldTrackingConfiguration()
#IBOutlet weak var sceneView: ARSCNView!
override func viewWillAppear(_ animated: Bool)
{
super.viewWillAppear(animated)
// Run the view's session
sceneView.session.run(configuration)
}
override func viewDidLoad()
{
super.viewDidLoad()
// Set the view's delegate
sceneView.delegate = self as? ARSCNViewDelegate
// Create a new scene
let scene = SCNScene()
// Set the scene to the view
sceneView.scene = scene
sceneView.autoenablesDefaultLighting = true
/* sceneView.debugOptions = [.showConstraints, .showLightExtents, ARSCNDebugOptions.showFeaturePoints, ARSCNDebugOptions.showWorldOrigin] */
}
override func viewDidAppear(_ animated: Bool)
{
setZombies()
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: (#selector(VRViewController.restartSession)), userInfo: nil, repeats: true)
}
override func didReceiveMemoryWarning()
{
super.didReceiveMemoryWarning()
}
/* MAIN FUNCTIONS */
func setZombies()
{
for i in 0..<number
{
let zombiePlane = zombies[i][0] as! CGPoint
let thetaPlane = zombies[i][1] as! Double
let xPlane = abs(zombiePlane.x - center.x)
let yPlane = abs(zombiePlane.y - center.y)
let distance = sqrt((xPlane*xPlane) + (yPlane*yPlane))
var theta3D:Double = thetaPlane * (180/Double.pi) - diff2D - 90 /* degrees */
theta3D = theta3D * (Double.pi/180) /* radians */
let x3D = Float(distance) * Float(cos(theta3D))
let z3D = Float(distance) * Float(sin(theta3D))
addZombies(i:i, x: x3D, y: -1.5, z: z3D)
}
}
func addZombies(i:Int, x: Float, y: Float, z: Float) {
guard let zombieScene = SCNScene(named: "art.scnassets/zombie/StrongZombie.DAE") else { return }
let zombieNode = SCNNode()
let zombieSceneChildNodes = zombieScene.rootNode.childNodes
for childNode in zombieSceneChildNodes {
zombieNode.addChildNode(childNode)
}
zombieNode.position = SCNVector3(x, y, z)
zombieNode.scale = SCNVector3(0.1, 0.1, 0.1)
sceneView.scene.rootNode.addChildNode(zombieNode)
nodes.append(zombieNode)
}
func restartSession()
{
/* self.sceneView.session.run(configuration, options: [.resetTracking]) */
for i in 0..<number
{
let theta3D = atan2(nodes[i].position.z, nodes[i].position.x)
let movement = (Float(speed)/5)
print(speed)
let distance = sqrt((nodes[i].position.x)*(nodes[i].position.x) + (nodes[i].position.z)*(nodes[i].position.z)) - movement
let x3D = Float(distance) * Float(cos(theta3D))
let z3D = Float(distance) * Float(sin(theta3D))
nodes[i].position = SCNVector3(x:x3D, y:-10, z:z3D)
}
}
/* SESSION FUNCTIONS */
func session(_ session: ARSession, didFailWithError error: Error)
{
// Present an error message to the user
}
func sessionWasInterrupted(_ session: ARSession)
{
// Inform the user that the session has been interrupted, for example, by presenting an overlay
}
func sessionInterruptionEnded(_ session: ARSession)
{
// Reset tracking and/or remove existing anchors if consistent tracking is required
}
}