usdz works, rcproject fails

Hi, I'm new to Xcode and I have a little problem I can't solve. I used the code that I attached. If I load the SpiralTest.usdz file everything works fine. If I load the SpiralTest.rcproject file it fails. But I have to use the rcproject-file. How do I have to customize the code. I tried to send the files with this message, but i can't choose .usdz or zip. But you can test ist with any other usdz and rcproject file. Thanks for your help. Thomas

import UIKit
import RealityKit
import ARKit



class ViewController: UIViewController {
   
  @IBOutlet var arView: ARView!
   

  override func viewWillAppear(_ animated: Bool){
    super.viewWillAppear(true)
    arView.session.delegate = self
    setupCustomObjectView()
    let tabGesture = UITapGestureRecognizer(target: self, action: #selector(onTap))
    arView.addGestureRecognizer(tabGesture)
  }
      
  func setupCustomObjectView () {
    arView.automaticallyConfigureSession = false
    let configuration = ARWorldTrackingConfiguration()
    configuration.planeDetection = [.horizontal, .vertical]
    configuration.environmentTexturing = .automatic
    arView.session.run(configuration)
  }
   
  @IBAction func onTap(recognizer: UITapGestureRecognizer) {
    let location = recognizer.location(in: arView)
    let results = arView.raycast(from: location, allowing: .estimatedPlane, alignment: .horizontal)
    if let firstResult = results.first {
      let anchor = ARAnchor(name: "SpiralTest.rcproject“, transform: firstResult.worldTransform)
      arView.session.add(anchor: anchor)
    } else {
      print("Object placement failed")
     
    }
  }
   
  func placeObject(name entityName: String, for anchor:ARAnchor){
    let entity = try! ModelEntity.loadModel(named: entityName)
    entity.generateCollisionShapes(recursive: true)
    arView.installGestures([.rotation, .scale], for: entity)
     
    let anchorEntity = AnchorEntity(anchor: anchor)
    anchorEntity.addChild(entity)
    arView.scene.addAnchor(anchorEntity)
  }
   
}

extension ViewController: ARSessionDelegate {
  func session(_ session: ARSession, didAdd anchors: [ARAnchor]) {
    for anchor in anchors {
      if let anchorObject = anchor.name, anchorObject == "SpiralTest.rcproject“ {
        placeObject(name: anchorObject, for: anchor)
      }
    }
  }
}
usdz works, rcproject fails
 
 
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