Environment Xcode: 16.2 VisionOS SDK 2.4 Swift 6.1 Targets: Apple Vision Pro (immersive space) Frameworks: ARKit, RealityKit, SwiftUI What I’m Trying to Do I have a view-model class PlacementManager that holds two AR providers: private var worldTracking: WorldTrackingProvider private var planeDetection: PlaneDetectionProvider I want to dynamically replace these providers in a setEnvironment(_:) method (so I can save/clear a JSON scene and restart ARKit). What’s Happening If I declare them as : private let worldTracking = WorldTrackingProvider() private let planeDetection = PlaneDetectionProvider() I get compile-errors when I later do: self.worldTracking = newWorldTracking // Cannot assign to property: 'worldTracking' is a 'let' constant If I change them to un-initialized vars: private var worldTracking: WorldTrackingProvider private var planeDetection: PlaneDetectionProvider then in my init() I get: self used in property access 'worldTracking' before all stored properties are initialized Code snipet @Observable final class PlacementManager : ObservableObject { private var worldTracking: WorldTrackingProvider private var planeDetection: PlaneDetectionProvider // … other props … @MainActor init() { // error: self.worldTracking used before init… planeAnchorHandler = PlaneAnchorHandler(rootEntity: root) persistenceManager = PersistenceManager( worldTracking: worldTracking, rootEntity: root ) // … } @MainActor func setEnvironment(env: Environnement) async { let newWorldTracking = WorldTrackingProvider() let newPlaneDetection = PlaneDetectionProvider() try await appState!.arkitSession.run( [ newWorldTracking, newPlaneDetection ] ) self.worldTracking = newWorldTracking self.planeDetection = newPlaneDetection // … } } What I’ve Tried Giving them default values at declaration (= WorldTrackingProvider()) Initializing them at the top of init() before any use Passing the new providers into arkitSession.run(...) My Question What is the recommended Swift-style pattern to declare and reassign these ARKit provider properties so that: They’re fully initialized before use in init(), and I can swap them out later in setEnvironment(...) without compiler errors? Any pointers (or links to forum threads / docs) would be greatly appreciated!

Goal : Drag a sphere across the room and track it's position Problem: The gesture seems to have no effect on the sphere ModelEntity. I don't know how to properly attach the gesture to the ModelEntity. Any help is great. Thank you import SwiftUI import RealityKit import RealityKitContent import Foundation @main struct testApp: App { @State var immersionStyle:ImmersionStyle = .mixed var body: some Scene { ImmersiveSpace { ContentView() } .immersionStyle(selection: $immersionStyle, in: .mixed, .full, .progressive) } } struct ContentView: View { @State private var lastPosition: SIMD3<Float>? = nil @State var subscription: EventSubscription? @State private var isDragging: Bool = false var sphere: ModelEntity { let mesh = MeshResource.generateSphere(radius: 0.05) let material = SimpleMaterial(color: .blue, isMetallic: false) let entity = ModelEntity(mesh: mesh, materials: [material]) entity.generateCollisionShapes(recursive: true) return entity } var drag: some Gesture { DragGesture() .targetedToEntity(sphere) .onChanged { _ in self.isDragging = true } .onEnded { _ in self.isDragging = false } } var body: some View { Text("Hello, World!") RealityView { content in //1. Anchor Entity let anchor = AnchorEntity(world: SIMD3<Float>(0, 0, -1)) let ball = sphere //1.2 add component to ball ball.components.set(InputTargetComponent()) //2. add anchor to sphere anchor.addChild(ball) content.add(anchor) subscription = content.subscribe(to: SceneEvents.Update.self) { event in let currentPosition = ball.position(relativeTo: nil) if let last = lastPosition, last != currentPosition { print("Sphere moved from \(last) to \(currentPosition)") } lastPosition = currentPosition } } .gesture(drag) } }

Goal : Drag a sphere across the room and track it's position Problem: The gesture seems to have no effect on the sphere ModelEntity. I don't know how to properly attach the gesture to the ModelEntity. Any help is great. Thank you import SwiftUI import Foundation import UIKit @main struct testApp: App { @State var immersionStyle:ImmersionStyle = .mixed var body: some Scene { ImmersiveSpace { ContentView() } .immersionStyle(selection: $immersionStyle, in: .mixed, .full, .progressive) } } struct ContentView: View { @State private var lastPosition: SIMD3? = nil @State var subscription: EventSubscription? @State private var isDragging: Bool = false var sphere: ModelEntity { let mesh = MeshResource.generateSphere(radius: 0.05) let material = SimpleMaterial(color: .blue, isMetallic: false) let entity = ModelEntity(mesh: mesh, materials: [material]) entity.generateCollisionShapes(recursive: true) return entity } var drag: some Gesture { DragGesture() .onChanged { _ in self.isDragging = true } .onEnded { _ in self.isDragging = false } } var body: some View { RealityView { content in //1. Anchor Entity let anchor = AnchorEntity(world: SIMD3<Float>(0, 0, -1)) let ball = sphere //2. add anchor to sphere anchor.addChild(ball) content.add(anchor) subscription = content.subscribe(to: SceneEvents.Update.self) { event in let currentPosition = ball.position(relativeTo: nil) if let last = lastPosition, last != currentPosition { print("Sphere moved from \(last) to \(currentPosition)") } lastPosition = currentPosition } } .gesture(drag) } }

In the section : Add transform logic to the main component There is the line : var state: GestureStateComponent = entity.gestureStateComponent ?? GestureStateComponent() When I try to add the same line. I have the error cannot find GestureStateComponent in scope. My imports : import SwiftUI import RealityKit import RealityKitContent An answer would be greatly appreciate it

I create a simple primitive shape and I want to add colors on each faces of the cube. I was thinking using Shape Graph, but I have no idea on how to specify each faces with a different color. Any lead or help would be great. This tech is new so help documentions is very low