QuickRealityKitTutorial.swift

import UIKit
import RealityKit
import Combine

class GameViewController: UIViewController {
    
    var sceneEventsUpdateSubscription: Cancellable!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let arView = ARView(frame: view.frame,
                            cameraMode: .nonAR,
                            automaticallyConfigureSession: false)
        view.addSubview(arView)
        
        let skyboxName = "aerodynamics_workshop_2k"
        let skyboxResource = try! EnvironmentResource.load(named: skyboxName)
        arView.environment.lighting.resource = skyboxResource
        arView.environment.background = .skybox(skyboxResource)
        
        var sphereMaterial = SimpleMaterial()
        sphereMaterial.metallic = MaterialScalarParameter(floatLiteral: 1)
        sphereMaterial.roughness = MaterialScalarParameter(floatLiteral: 0)
        
        let sphereEntity = ModelEntity(mesh: .generateSphere(radius: 1), materials: [sphereMaterial])
        let sphereAnchor = AnchorEntity(world: .zero)
        sphereAnchor.addChild(sphereEntity)
        arView.scene.anchors.append(sphereAnchor)

        let camera = PerspectiveCamera()
        camera.camera.fieldOfViewInDegrees = 60
        
        let cameraAnchor = AnchorEntity(world: .zero)
        cameraAnchor.addChild(camera)
        
        arView.scene.addAnchor(cameraAnchor)

        let cameraDistance: Float = 3
        var currentCameraRotation: Float = 0
        let cameraRotationSpeed: Float = 0.01

        sceneEventsUpdateSubscription = arView.scene.subscribe(to: SceneEvents.Update.self) { _ in
            let x = sin(currentCameraRotation) * cameraDistance
            let z = cos(currentCameraRotation) * cameraDistance
            
            let cameraTranslation = SIMD3<Float>(x, 0, z)
            let cameraTransform = Transform(scale: .one,
                                            rotation: simd_quatf(),
                                            translation: cameraTranslation)
            
            camera.transform = cameraTransform
            camera.look(at: .zero, from: cameraTranslation, relativeTo: nil)

            currentCameraRotation += cameraRotationSpeed
        }
    }
}

where should I place "aerodynamics_workshop_2k" in Xcode project bundle? Thanks

Just follow the tutorial strictly and all works well:
https://rozengain.medium.com/quick-realitykit-tutorial-programmatic-non-ar-setup-cafaf61e9884