What is the current [most recent] best practice to instancing Meshes in RealityKit? I see both MeshInstanceComponent and MeshInstanceCollection. My intent is to bind a transform to a Circle Agent (GameplayKit Agent), and feed that result to Instancing.

Problem Summary After upgrading to iOS 26.1 and 26.2, I'm experiencing a particle positioning bug in RealityKit where ParticleEmitterComponent particles render at an incorrect offset relative to their parent entity. This behavior does not occur on iOS 18.6.2 or earlier versions, suggesting a regression introduced in the newer OS builds. Environment Details Operating System: iOS 26.1 & iOS 26.2 Framework: RealityKit Xcode Version: 16.2 (16C5032a) Expected vs. Actual Behavior Expected: Particles should render at the position of the entity to which the ParticleEmitterComponent is attached, matching the behavior on iOS 18.6.2 and earlier. Actual: Particles appear away from their parent entity, creating a visual misalignment that breaks the intended AR experience. Steps to Reproduce Create or open an AR application with RealityKit that uses particle components Attach a ParticleEmitterComponent to an entity via a custom system Run the application on iOS 26.1 or iOS 26.2 Observe that particles render at an offset position away from the entity Minimal Code Example Here's the setup from my test case: Custom Component & System: struct SparkleComponent4: Component {} class SparkleSystem4: System { static let query = EntityQuery(where: .has(SparkleComponent4.self)) required init(scene: Scene) {} func update(context: SceneUpdateContext) { for entity in context.scene.performQuery(Self.query) { // Only add once if entity.components.has(ParticleEmitterComponent.self) { continue } var newEmitter = ParticleEmitterComponent() newEmitter.mainEmitter.color = .constant(.single(.red)) entity.components.set(newEmitter) } } } AR Setup: let material = SimpleMaterial(color: .gray, roughness: 0.15, isMetallic: true) let model = Entity() model.components.set(ModelComponent(mesh: boxMesh, materials: [material])) model.components.set(SparkleComponent4()) model.position = [0, 0.05, 0] model.name = "MyCube" let anchor = AnchorEntity(.plane(.horizontal, classification: .any, minimumBounds: [0.2, 0.2])) anchor.addChild(model) arView.scene.addAnchor(anchor) Questions for the Community Has anyone else encountered this particle positioning issue after updating to iOS 26.1/26.2? Are there known workarounds or configuration changes to ParticleEmitterComponent that restore correct positioning? Is this a confirmed bug, or could there be a change in coordinate system handling or transform inheritance that I'm missing? Additional Information I've already submitted this issue via Feedback Assistant(FB21346746)

I have a 3D model with morphing animation that works correctly in Blender. I exported this model as a USDZ file and tried to display it in an Xcode-developed visionOS app, but the morphing animation does not play. What I Have Tried: Morphing animation works correctly in Blender. After exporting to USDZ, the morphing animation does not play in the Xcode app. Linear motion animations (such as object movement) work fine. Behavior in Reality Converter: GLB files do not display. USDZ files load, but morphing animations do not play. What I Want to Know: Is there a way to play morphing animations in an Xcode-developed app? Does RealityKit support morphing animations? Can morphing animations be played in an Xcode-developed app? If RealityKit does not support morphing animations, what alternative methods can be used to play them? I am looking for a way to use the existing animations without recreating them. Additional Information: I have both the Blender file (where animations work) and the USDZ file (where animations do not play). I am developing a visionOS app using Xcode. Any advice or solutions would be greatly appreciated. Thank you in advance!

Hi, How to enable multitouch on ARView? Touch functions (touchesBegan, touchesMoved, ...) seem to only handle one touch at a time. In order to handle multiple touches at a time with ARView, I have to either: Use SwiftUI .simultaneousGesture on top of an ARView representable Position a UIView on top of ARView to capture touches and do hit testing by passing a reference to ARView Expected behavior: ARView should capture all touches via touchesBegan/Moved/Ended/Cancelled. Here is what I tried, on iOS 26.1 and macOS 26.1: ARView Multitouch The setup below is a minimal ARView presented by SwiftUI, with touch events handled inside ARView. Multitouch doesn't work with this setup. Note that multitouch wouldn't work either if the ARView is presented with a UIViewController instead of SwiftUI. import RealityKit import SwiftUI struct ARViewMultiTouchView: View { var body: some View { ZStack { ARViewMultiTouchRepresentable() .ignoresSafeArea() } } } #Preview { ARViewMultiTouchView() } // MARK: Representable ARView struct ARViewMultiTouchRepresentable: UIViewRepresentable { func makeUIView(context: Context) -> ARView { let arView = ARViewMultiTouch(frame: .zero) let anchor = AnchorEntity() arView.scene.addAnchor(anchor) let boxWidth: Float = 0.4 let boxMaterial = SimpleMaterial(color: .red, isMetallic: false) let box = ModelEntity(mesh: .generateBox(size: boxWidth), materials: [boxMaterial]) box.name = "Box" box.components.set(CollisionComponent(shapes: [.generateBox(width: boxWidth, height: boxWidth, depth: boxWidth)])) anchor.addChild(box) return arView } func updateUIView(_ uiView: ARView, context: Context) { } } // MARK: ARView class ARViewMultiTouch: ARView { required init(frame: CGRect) { super.init(frame: frame) /// Enable multi-touch isMultipleTouchEnabled = true cameraMode = .nonAR automaticallyConfigureSession = false environment.background = .color(.gray) /// Disable gesture recognizers to not conflict with touch events /// But it doesn't fix the issue gestureRecognizers?.forEach { $0.isEnabled = false } } required dynamic init?(coder decoder: NSCoder) { fatalError("init(coder:) has not been implemented") } override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) { for touch in touches { /// # Problem /// This should print for every new touch, up to 5 simultaneously on an iPhone (multi-touch) /// But it only fires for one touch at a time (single-touch) print("Touch began at: \(touch.location(in: self))") } } } Multitouch with an Overlay This setup works, but it doesn't seem right. There must be a solution to make ARView handle multi touch directly, right? import SwiftUI import RealityKit struct MultiTouchOverlayView: View { var body: some View { ZStack { MultiTouchOverlayRepresentable() .ignoresSafeArea() Text("Multi touch with overlay view") .font(.system(size: 24, weight: .medium)) .foregroundStyle(.white) .offset(CGSize(width: 0, height: -150)) } } } #Preview { MultiTouchOverlayView() } // MARK: Representable Container struct MultiTouchOverlayRepresentable: UIViewRepresentable { func makeUIView(context: Context) -> UIView { /// The view that SwiftUI will present let container = UIView() /// ARView let arView = ARView(frame: container.bounds) arView.autoresizingMask = [.flexibleWidth, .flexibleHeight] arView.cameraMode = .nonAR arView.automaticallyConfigureSession = false arView.environment.background = .color(.gray) let anchor = AnchorEntity() arView.scene.addAnchor(anchor) let boxWidth: Float = 0.4 let boxMaterial = SimpleMaterial(color: .red, isMetallic: false) let box = ModelEntity(mesh: .generateBox(size: boxWidth), materials: [boxMaterial]) box.name = "Box" box.components.set(CollisionComponent(shapes: [.generateBox(width: boxWidth, height: boxWidth, depth: boxWidth)])) anchor.addChild(box) /// The view that will capture touches let touchOverlay = TouchOverlayView(frame: container.bounds) touchOverlay.autoresizingMask = [.flexibleWidth, .flexibleHeight] touchOverlay.backgroundColor = .clear /// Pass an arView reference to the overlay for hit testing touchOverlay.arView = arView /// Add views to the container. /// ARView goes in first, at the bottom. container.addSubview(arView) /// TouchOverlay goes in last, on top. container.addSubview(touchOverlay) return container } func updateUIView(_ uiView: UIView, context: Context) { } } // MARK: Touch Overlay View /// A UIView to handle multi-touch on top of ARView class TouchOverlayView: UIView { weak var arView: ARView? override init(frame: CGRect) { super.init(frame: frame) isMultipleTouchEnabled = true isUserInteractionEnabled = true } required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") } override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) { let totalTouches = event?.allTouches?.count ?? touches.count print("--- Touches Began --- (New: \(touches.count), Total: \(totalTouches))") for touch in touches { let location = touch.location(in: self) /// Hit testing. /// ARView and Touch View must be of the same size if let arView = arView { let entity = arView.entity(at: location) if let entity = entity { print("Touched entity: \(entity.name)") } else { print("Touched: none") } } } } override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) { let totalTouches = event?.allTouches?.count ?? touches.count print("--- Touches Cancelled --- (Cancelled: \(touches.count), Total: \(totalTouches))") } }

Starting with iOS 18.0 beta 1, I've noticed that RealityKit frequently crashes in the simulator when an app launches and presents an ARView. I was able to create a small sample app with repro steps that demonstrates the issue, and I've submitted feedback: FB16144085 I've included a crash log with the feedback. If possible, I'd appreciate it if an Apple engineer could investigate and suggest a workaround. It's awkward to be restricted to the iOS 17 simulator, which does not exhibit this behavior. Please let me know if there's anything I can do to help. Thank you.

Hi all im having a variety of issues with gamekit matchmaking. On the simulator the matchmaking ui pops up and I can click Quick Match, then immediately "Failed to find Players" this is the same with a real Apple ID and a sandbox account. If I use real devices the app at least discovers a match, but then the match none of the delegate methods for the match ever get called and the logs are filled with socket not connected and various errors. My questions are: Should match making via quick match work in the simulator, I have seen tutorial videos etc of this working, but I can't seem to get it to work. How do people debug issues with GameCenter / Gamekit to find out why its not able to connect? Many thanks in advance

I am trying to install the Game Porting Toolkit 2.1 according to the Readme file provided with the toolkit. When I run the following command: WINEPREFIX=~/my-game-prefix brew --prefix game-porting-toolkit/bin/wine64 winecfg I get an error message: zsh: no such file or directory: /usr/local/opt/game-porting-toolkit/bin/wine64 I don't know how to resolve this. When I type in the command which brew , I get the path /usr/local/bin/brew What am I doing wrong?

I’m building an app that uses RealityKit and specifically ARConfiguration.FrameSemantics.personSegmentationWithDepth. The goal is to insert an AR object into the scene behind a person, and an additional AR object in front of the person, while being as photo realistic as possible. Through testing, I’ve noticed that many times, the edges of the person segmentation mask are not well matched to the actual person, and parts of the person are transparent, with the AR object bleeding through. It’s sort of like a “bad green screen” effect, which I’d expect to see a little bit, but not to this extent. I’ve been testing on iPhone 16, iPhone 14 Pro, iPad Pro 12.9 inch 6th Generation, and iPhone 12 Pro, with similar results across all devices. I’m wondering what else I can do to improve this… either code changes, platform (like different iPhone models), or environment (like lighting, distance, etc). Attaching some example screen grabs and a minimum reproducible code sample. Appreciate any insights! import ARKit import SwiftUI import RealityKit struct RealityViewContainer: UIViewRepresentable { func makeUIView(context: Context) -> ARView { let arView = ARView(frame: .zero) arView.environment.sceneUnderstanding.options.insert(.occlusion) arView.renderOptions.insert(.disableMotionBlur) arView.renderOptions.insert(.disableDepthOfField) let configuration = ARWorldTrackingConfiguration() configuration.planeDetection = [.horizontal] if ARWorldTrackingConfiguration.supportsFrameSemantics(.personSegmentationWithDepth) { configuration.frameSemantics.insert(.personSegmentationWithDepth) } arView.session.run(configuration) arView.session.delegate = context.coordinator context.coordinator.arView = arView } func makeCoordinator() -> Coordinator { Coordinator(self) } class Coordinator: NSObject, ARSessionDelegate { var parent: RealityViewContainer var floorAnchor: ARPlaneAnchor? init(_ parent: RealityViewContainer) { self.parent = parent } func session(_ session: ARSession, didAdd anchors: [ARAnchor]) { if let arView,floorAnchor == nil { for anchor in anchors { if let horizontalPlaneAnchor = anchor as? ARPlaneAnchor, horizontalPlaneAnchor.alignment == .horizontal, horizontalPlaneAnchor.transform.columns.3.y < arView.cameraTransform.translation.y { // filter out ceiling floorAnchor = horizontalPlaneAnchor let backgroundEntity = BackgroundEntity() let anchorEntity = AnchorEntity(anchor: horizontalPlaneAnchor) anchorEntity.addChild(background) let foregroundEntity = ForegroundEntity() backgroundEntity.addChild(foregroundEntity) arView.scene.addAnchor(anchorEntity) arView.installGestures([.rotation, .translation], for: backgroundEntity) break // Stop after adding the first horizontal plane (floor) } } } } } }

Hi, Introducing Swift Concurrency to my Metal app has been a bit challenging as Swift Concurrency is limited by the cooperative thread pool. GPU work is obviously not CPU bound and can block forward moving progress, especially when using waitUntilCompleted on the command buffer. For concurrent render work this has the potential of under utilizing the CPU and even creating dead locks. My question is, what is the Metal's teams general recommendation when it comes to concurrency? It seems to me that Dispatch or OperationQueues are still the preferred way for Metal bound tasks in order to gain maximum performance? To integrate with Swift Concurrency my idea is to use continuations that kick off render jobs via Dispatch or Queues? Would this be the best solution to bridge async tasks with Metal work? Thanks!

I’ve added two recurring leaderboards to my app and the user interface for the Game Center leaderboards pops up when expected and it lists the leaderboards but when you click on them it says “Have Fun With Friends” and lists some of my contacts instead of any scores. The status under Apple Connect is “Not Live” and I’m wondering how to activate them. App has been approved for external beta testing. On a related note, on my iPad it doesn’t display correctly, it says “Game Center” at the top but the rest of the UI doesn’t appear, just blackness.

Problem Summary After upgrading to iOS 26.1 and 26.2, I'm experiencing a particle positioning bug in RealityKit where ParticleEmitterComponent particles render at an incorrect offset relative to their parent entity. This behavior does not occur on iOS 18.6.2 or earlier versions, suggesting a regression introduced in the newer OS builds. Environment Details Operating System: iOS 26.1 & iOS 26.2 Framework: RealityKit Xcode Version: 16.2 (16C5032a) Expected vs. Actual Behavior Expected: Particles should render at the position of the entity to which the ParticleEmitterComponent is attached, matching the behavior on iOS 18.6.2 and earlier. Actual: Particles appear away from their parent entity, creating a visual misalignment that breaks the intended AR experience. Steps to Reproduce Create or open an AR application with RealityKit that uses particle components Attach a ParticleEmitterComponent to an entity via a custom system Run the application on iOS 26.1 or iOS 26.2 Observe that particles render at an offset position away from the entity Minimal Code Example Here's the setup from my test case: Custom Component & System: struct SparkleComponent4: Component {} class SparkleSystem4: System { static let query = EntityQuery(where: .has(SparkleComponent4.self)) required init(scene: Scene) {} func update(context: SceneUpdateContext) { for entity in context.scene.performQuery(Self.query) { // Only add once if entity.components.has(ParticleEmitterComponent.self) { continue } var newEmitter = ParticleEmitterComponent() newEmitter.mainEmitter.color = .constant(.single(.red)) entity.components.set(newEmitter) } } } AR Setup: let material = SimpleMaterial(color: .gray, roughness: 0.15, isMetallic: true) let model = Entity() model.components.set(ModelComponent(mesh: boxMesh, materials: [material])) model.components.set(SparkleComponent4()) model.position = [0, 0.05, 0] model.name = "MyCube" let anchor = AnchorEntity(.plane(.horizontal, classification: .any, minimumBounds: [0.2, 0.2])) anchor.addChild(model) arView.scene.addAnchor(anchor) Questions for the Community Has anyone else encountered this particle positioning issue after updating to iOS 26.1/26.2? Are there known workarounds or configuration changes to ParticleEmitterComponent that restore correct positioning? Is this a confirmed bug, or could there be a change in coordinate system handling or transform inheritance that I'm missing? Additional Information I've already submitted this issue via Feedback Assistant(FB21346746)

In the Creating A 3D Application With Hydra Rendering tutorial on the Apple Developer website, on the last step where I execute this command: cmake -S ~/Users/macuser/CreatingA3DApplicationWithHydraRendering/ -B ~/Users/macuser/CreatingA3DApplicationWithHydraRendering/ I keep getting an error: CMake Error at CMakeLists.txt:5 (include): include could not find requested file: /Users/macuser/USDInstall/bin/pxrConfig.cmake I've tried to follow the instructions as mentioned in the README.md file included in the project files at least 5 times as well as moving the pxrConfig.cmake file around and copying it in different folders, then executed the command and was still unsuccessful into generating the proper file expected to compile and render the HydraPlayer renderer. How do I get cmake to generate the Xcode file to create the HydraPlayer renderer?

I am trying the simplest use of attachment in realityKit and get Contextual closure type @MainActor, @Sendable (inout RealityViewCameraContent) async -> void expects 1 argument, but 2 were used in closure body. Also i get cannot find Attachment in scope

The simplest realityView (content, attachments in ... causes Contextual closure expects 1 argument but 2 were used in closure body. I have checked every example and i cannot understand why i get this error regardless of any content. Note: i have added Attachment(id: "test") to the attachment closure and get Attachment not is scope. imported both realityKit and SwiftUI.

Is the pseudocode below thread-safe? Imagine that the Main thread sets the CAMetalLayer's drawableSize to a new size meanwhile the rendering thread is in the middle of rendering into an existing MTLDrawable which does still have the old size. Is the change of metalLayer.drawableSize thread-safe in the sense that I can present an old MTLDrawable which has a different resolution than the current value of metalLayer.drawableSize? I assume that setting the drawableSize property informs Metal that the next MTLDrawable offered by the CAMetalLayer should have the new size, right? Is it valid to assume that "metalLayer.drawableSize = newSize" and "metalLayer.nextDrawable()" are internally synchronized, so it cannot happen that metalLayer.nextDrawable() would produce e.g. a MTLDrawable with the old width but with the new height (or a completely invalid resolution due to potential race conditions)? func onWindowResized(newSize: CGSize) { // Called on the Main thread metalLayer.drawableSize = newSize } func onVsync(drawable: MTLDrawable) { // Called on a background rendering thread renderer.renderInto(drawable: drawable) }

I'm trying to understand how Apple handles dragging windows around in an immersive space. 3d Gestures seem to be only half of the solution in that they are great if you're standing still and want to move the window an exaggerated amount around the environment, but if you then start walking while dragging, the amplified gesture sends the entity flying off into the distance. It seems they quickly transition from one coordinate system to another depending on if the user is physically moving. If you drag a window and start walking the movement suddenly matches your speed. When you stop moving, you can push and pull the windows around again like a super hero. Am I missing something obvious in how to copy this behavior? Hello world, which uses the 3d gesture has the same problem. You can move the world around but if you walk with it, it flies off. Are they tracking the head movement and if it's moved more than a certain amount it uses that offset instead? Is there anything out of the box that can do this before I try and hack my own solution?

Hi, I uptaded to the 15.2 my system. It was Turkish and I change the English for AI. But Image Playground is not working. My Playground app has been stuck at Downloading support for Image Playground now for about 4-5 days.

View Layout Add the following views in a view controller: Label View A, with a subview of the same size: MTKView A View B, with a subview of the same size: MTKView B Refresh Rates of Each View The label view refreshes at 60fps (driven by CADisplayLink). MTKView A and B refresh at 15fps. MTKView Implementation Details The corresponding CAMetalLayer's maximumDrawableCount is set to 2, changed to double buffering. The scheduling mechanism is modified; drawing is not driven by the internal loop but is done manually. The draw call is triggered immediately upon receiving a frame. self.metalView.enableSetNeedsDisplay = NO; self.metalView.paused = YES; A new high-priority queue is created for drawing, instead of handling it on the main queue. MTKView Latency Tracking The GPU completion time T1 is observed through the addCompletedHandler callback of the CommandBuffer. The presentation time T2 of the frame is observed through the addPresentedHandler callback of the currentDrawable in MTKView. Testing shows that T2 - T1 > 16.6ms (the Vsync period at 60Hz). This means that after the GPU rendering in MTLView is finished, the frame is not actually displayed at the next Vsync instruction but only at the Vsync instruction after that. I believe there is an extra 16.6ms of latency here, which I want to eliminate by adjusting the rendering mechanism. Observation from Instruments From Instruments, the Surface presentation aligns with the above test results. After the Metal encoder finishes, the Surface in Display switches only after the next-next Vsync instruction. See the image in the link for details. Questions According to a beginner's understanding, after MTKView's GPU rendering is finished, the next Vsync instruction should officially display (make it visible). However, this is not what is observed. Does the subview MTKView need to wait for another Vsync cycle to be drawn to the actual display buffer? The label updates its text at 60fps, so the entire interface should be displayed at 60fps. Is the content of MTKView not synchronized when the display happens? Explanation of the Reasoning Behind Some MTKView Code Details Changing from the default triple buffering to double buffering helps reduce the latency introduced by rendering. Not using MTKView's own scheduling mechanism but using manual triggering of the draw method is because MTKView's own scheduling mechanism is driven by CADisplayLink. Therefore, if a frame falls within a Vsync window, it needs to wait for the next Vsync window to trigger the draw operation, which introduces waiting latency.

Hi, seems MSL is missing support for a clock() shader instruction available in other graphics APIs like Vulkan or OpenGL for example.. useful for counting cost in number of clock cycles of some code insider shader with much finer granularity than launching a micro kernel with same instructions and measuring cycles cost from CPU.. also useful for MoltenVK to support that extensions.. thanks..

I'm trying to get video material to work on an imported 3D asset, and this asset is a USDC file. There's actually an example in this WWDC video from Apple. You can see it running on the flag in this airplane, but there are no examples of this, and there are no other examples on the internet. Does anybody know how to do this? You can look at 10:34 in this video. https://developer.apple.com/documentation/realitykit/videomaterial