Discuss Spatial Computing on Apple Platforms.

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Background Assets in VisionOS
Hi, I'm working on a VisionOS app and would like to integrate Background Assets to download large files after the app is installed. I'm wondering what would happen if the user takes off the headset while a background asset is being downloaded. Would it continue downloading or would the download be stopped/paused? I was looking for a way to download large assets while the user is not wearing the Vision Pro, is there any other alternative? Thanks in advance.
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Jun ’25
Request for gaze data in fully immersive Metal apps
Hi, We are trying to port our Unity app from other XR devices to Vision Pro. Thus it's way easier for us to use the Metal rendering layer, fully immersive. And to stay true to the platform, we want to keep the gaze/pinch interaction system. But we just noticed that, unlike Polyspatial XR apps, VisionOS XR in Metal does not provide gaze info unless the user is actively pinching... Which forbids any attempt to give visual feedback on what they are looking at (buttons, etc). Is this planned in Apple's roadmap ? Thanks
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566
Feb ’25
Scene's origin relative to portal's window?
I am experimenting with RealityKit to set up a portal. Everything works, but I was wondering where the scene's origin is with respect to the front of the portal window? From experiments, the origin's X and Y appear to be at the center of the portal window, while the origin's Z appearing to be about a meter behind the portal window. Is this (at least roughly) correct? Is it documented anywhere? PS. I began with the standard visionOS app and edited the Reality Composer Pro file to create the scene.
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Mar ’25
RealityKit entity.write(to:) generates fatal protection error
My app for framing and arranging pictures from Photos on visionOS allows users to write the arrangements they create to .reality files using RealityKit entity.write(to:) that they then display to customers on their websites. This works perfectly on visionOS 2, but fails with a fatal protection error on visionOS 26 beta 1 and beta 2 when write(to:) attempts to write to its internal cache: 2025-06-29 14:03:04.688 Failed to write reality file Error Domain=RERealityFileWriterErrorDomain Code=10 "Could not create parent folders for file path /var/mobile/Containers/Data/Application/81E1DDC4-331F-425D-919B-3AB87390479A/Library/Caches/com.GeorgePurvis.Photography.FrameItVision/RealityFileBundleZippingTmp_A049685F-C9B2-479B-890D-CF43D13B60E9/41453BC9-26CB-46C5-ADBE-C0A50253EC27." UserInfo={NSLocalizedDescription=Could not create parent folders for file path /var/mobile/Containers/Data/Application/81E1DDC4-331F-425D-919B-3AB87390479A/Library/Caches/com.GeorgePurvis.Photography.FrameItVision/RealityFileBundleZippingTmp_A049685F-C9B2-479B-890D-CF43D13B60E9/41453BC9-26CB-46C5-ADBE-C0A50253EC27.} Has anyone else encountered this problem? Do you have a workaround? Have you filed a feedback? ChatGPT analysis of the error and my code reports: Why there is no workaround • entity.write(to:) is a black box — you cannot override where it builds its staging bundle • it always tries to create those random folders itself • you cannot supply a parent or working directory to RealityFileWriter • so if the system fails to create that folder, you cannot patch it 👉 This is why you see a fatal error with no recovery. See also feedbacks: FB18494954, FB18036627, FB18063766
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Jul ’25
spatial-backdrop feature available yet?
In WWDC25 session What’s new for the spatial web, the presenter showed creating an immersive environment for a web page by adding to the page's HEAD section <link rel="spatial-backdrop" href="office.usdz" environmentmap="lighting.hdr"> My first attempt failed, and I am trying to track down why. Before I search all the potential failure paths, I wanted to ask the community, Is this feature available in the latest visionOS 26 beta? I haven't seen anyone talk about their use of the feature yet.
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211
Aug ’25
Control mirroring of Apple Vision Pro on any devices ?
Hi ! I'm new on this forum, so if I need to update this post to have more info, or anything else, please let me know. I'm using the Apple Vision Pro to develop some app (with unity). To demonstrate what the user see on the headset, I would like to mirror the view on a device (an iPad in this case). I managed to do this without any issue. My problem is that, in the Vision Pro, I have an interface that the user can interact with. But I would like to be able to manage myself the interface on the iPad. What I mean is that the user can (or can't, doesn't matter) see the interface in the headset, and the interface is controlled by myself on the iPad. Is there any way to do this ? Is this a question I should ask on unity's forum ? (I don't think so, because it should be related to the mirroring function non ?)
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Mar ’25
How to handle tasks when the Vision Pro is taken off?
I have a grpc server running inside of a task. When the user takes the headset off, the grpc server will no longer work when they put the headset back on. I would like to have this action detected so that I can cancel the task (which will effectively close the grpc server). I am also using a visual indicator to let the user know if the server is running, but it will not accurately reflect the state of the server when removing and putting back on the headset.
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290
Mar ’25
Imitating a grip on an object
I'm playing about with the hand tracking systems in reality kit / Vision Pro I thought it would be interesting if I could attach a virtual object to a hand when the hand is gripping (thought it would be fun to attach a basic cylinder to mimic a wand from Harry Potter) I'm able to detect when the user is gripping but having trouble placing an object as though it's within the hand. The simplest version of this is using an AnchorEntity pointing to the user's palm which kind of works, but quickly breaks the illusion when you rotate the wrist or hand. It seems as though I will have to roll my own anchor entity using the various points of the user's hand and I thought calculating some median point between the thumb and little finger tips would be a good start but it's proven a little difficult as we need both rotation and position. I'm already out of my depth with reality kit and matrices (and thanks to ChatGPT) I have some code, but as soon as I apply the position manually (as opposed to a hand anchor entity) it fails to render on the user's hand. It feels like this should already have been something someone has looked in to, any ideas on what might be the issue here? Note: HandTrackingSystem.handTracking is a HandTrackingProvider() guard let anchors = HandTrackingSystem.handTracking.latestAnchors.leftHand else { return } if let thumb = anchors.handSkeleton?.joint(.thumbTip), let little = anchors.handSkeleton?.joint(.littleFingerTip) { let thumbPos = simd_make_float3(thumb.anchorFromJointTransform.columns.3) let littlePos = simd_make_float3(little.anchorFromJointTransform.columns.3) let midPos = (thumbPos + littlePos) / 2 let direction = normalize(littlePos - thumbPos) let rotation = simd_quatf(from: [0, 1, 0], to: direction) wandEntity.transform.translation = midPos wandEntity.transform.rotation = rotation content.add(wandEntity) }
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Jul ’25
VisionOS Beta 3 spatial sculpting apple sample crash
Hello since updating to beta 3 the sculpting sample app doesn't work it crashes on running. seems to be something in AnchorEntity or AccessoryAnchoringSource Referenced from: <00B81486-1A74-30A0-B75B-4B39E3AF57DF> /private/var/containers/Bundle/Application/3D2EBF59-19F0-4BF4-8567-6962AA36A2C6/delete.app/delete.debug.dylib Expected in: <BAA9B221-78A1-3B99-AA2F-B8DFCD179FC7> /System/Library/Frameworks/RealityFoundation.framework/RealityFoundation
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Jul ’25
Automatic Plane Measurements like in the Apple Measure App
I’m working on an iOS app that needs to measure the area of planes or surfaces, like the length and width of objects, just like the Apple Measure app does. I’ve been exploring ARKit, but I’m curious if there are any APIs or techniques that can help automate the process of detecting and measuring planes. Specifically, I’m looking for a way to automatically detect and measure planes (e.g., from a top-down view). For example: Measuring a box width and length. I have attached a screenshot and a video of the Apple Measure App doing it. Does Apple provide any tools or APIs for this, or are there any best practices I should know about? I’d love to hear from anyone who’s tackled something similar. Video: https://drive.google.com/file/d/1BxM7fIbFxsCsYwY7w8ZxIeq_4WTGkkwA/view?usp=drive_link
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711
Jan ’25
CameraFrameProvider distortion correction
Hi, I'm trying to correct the lens distortion in frames provided by Enterprise API camera frame provider. The frames provided seem to have only in/extrinsics info, but not the distortion lookup table. Is there some magic setting, or function to do that (I can't seem to find anything like this)? Or is there a way to use AVCameraCalibrationData together with provider?
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400
Mar ’25
ReplayKit start and stop capture breaks and give me an error when switching from Immersive to Mixed and back.
Hi, I'm developing a virtual camera system using ReplayKit to capture scene video by directly accessing raw video buffers. The capture mechanism works flawlessly when repeatedly starting and stopping video capture within a continuous immersive environment. However, a critical issue arises when interrupting the immersive space: Step 1: Enter immersive environment and start and stop capture videos(Multiple times with no issues) Step 2: Press the crown button to exit the immersive environment Step 3: Return to the immersive space subsequently Step 4: Attempt to start the video capture At this point, the startCapture method throws an unexpected error, disrupting the video capture workflow. This is the Xcode error that I see " [ERROR] -[RPScreenRecorder startCaptureWithHandler:completionHandler:]_block_invoke_2:500 failed to start due to error: Error Domain=com.apple.ReplayKit.RPRecordingErrorDomain Code=-5803 "Recording failed to start" UserInfo={NSLocalizedDescription=Recording failed to start}" I have tried all possible ways to stopCapture including OnDisappear and other methods and nothing seems to solve this.
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300
Mar ’25
I want to know the update principle of the `RealityView`.
Here is the code snippets. struct RealityViewTestView: View { @State private var texts: [String] = [] var body: some View { RealityView { content, attachments in } update: { content, attachments in for text in texts { if let textEntity = attachments.entity(for: text) { textEntity.position.x = Float.random(in: -0.1...0.1) content.add(textEntity) } } } attachments: { ForEach(texts, id: \.self) { text in Attachment(id: text) { Text(text) .padding() .glassBackgroundEffect() } } } .toolbar { ToolbarItem { Button("Add") { texts.append(String(UUID().uuidString.prefix(6))) } } ToolbarItem { Button("Remove") { texts.remove(at: Int.random(in: 0..<texts.count)) } } } } } struct RealityViewTestView: View { @State private var texts: [String] = [] @State private var entities: [Entity] = [] var body: some View { RealityView { content, attachments in } update: { content, attachments in // for text in texts { // if let textEntity = attachments.entity(for: text) { // textEntity.position.x = Float.random(in: -0.1...0.1) // content.add(textEntity) // } // } for entity in entities { content.add(entity) } } attachments: { ForEach(texts, id: \.self) { text in Attachment(id: text) { Text(text) .padding() .glassBackgroundEffect() } } } .toolbar { ToolbarItem { Button("Add") { //texts.append(String(UUID().uuidString.prefix(6))) let m = ModelEntity(mesh: .generateSphere(radius: 0.1), materials: [SimpleMaterial(color: .white, isMetallic: false)]) m.position.x = Float.random(in: -0.2...0.2) entities.append(m) } } ToolbarItem { Button("Remove") { //texts.remove(at: Int.random(in: 0..<texts.count)) entities.removeLast() } } } } } About the first code snippet, when I remove an element from the texts, why content can automatically remove the corresponding entity? And about the second code snippet, content do not automatically remove the corresponding entity. I am very curious.
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433
Jan ’25
Gaze, Eye Tracking responsive Stuff
I am wondering, is it possible to somehow configure a 3D object to respond to the gaze of a person, like change colors of some parts of the 3D-Model where a person is looking, i.e. where a person's gaze lands on the surface of the 3D-model ? For example, if there is a 3D model of a Cool Dragon 🐉 in the physical space of a person, when seen through with the mixed reality view, of a VisionPro. Now, it would be really cool to change only the color, or make some specific parts of the dragon skin shimmer, but only in the areas where a person is looking. Is this possible ? Is it do-able with eye-tracking of VisionPro ? Any advice would be appreciated. 🤝 🤓 I am new to iOS and VisionOS development.
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227
Mar ’25
RotateGesture3D auto constrained to axis
Hi, On visionOS to manage entity rotation we can rely on RotateGesture3D. We can even with the constrainedToAxis parameter authorize only rotation on an x, y or z axis or even make combinations. What I want to know is if it is possible to constrain the rotation on axis automatically. Let me explain, the functionality that I would like to implement is to constrain the rotation on an axis only once the user has started his gesture. The initial gesture the user makes should let us know which axis they want to rotate on. This would be equivalent to activating a constraint automatically on one of the axes, as if we were defining the gesture on one of the axes. RotateGesture3D(constrainedToAxis: .x) RotateGesture3D(constrainedToAxis: .y) RotateGesture3D(constrainedToAxis: .z) Is it possible to do this? If so, what would be the best way to do it? A code example would be greatly appreciated. Regards Tof
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Feb ’25
RealityKit Entity ComponentSet does not conform to Sequence?
Hello, I'm trying to view the components of an Entity I'm creating in RealityKit by reading from a USDZ file. I have the following code snippet in my app. if let appleEntity = try? Entity.loadModel(named: "apple_tile") { let c = appleEntity.components for comp in c { // <- compiler error here print(comp) } } The compiler error I'm receiving says "For-in loop requires 'Entity.ComponentSet' to conform to 'Sequence'". However, I thought this was the case, according to the documentation for Entity.ComponentSet? Curious if anyone else has had this problem. Running XCode 15.4, and my Swift version is xcrun swift -version swift-driver version: 1.90.11.1 Apple Swift version 5.10 (swiftlang-5.10.0.13 clang-1500.3.9.4) Target: x86_64-apple-macosx14.0
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411
Mar ’25
VisionOS: Detect plane to place objects issue for animated objects
Hi, I have used the template code for Plane Detection and placing models on them from here https://developer.apple.com/documentation/visionos/placing-content-on-detected-planes This source code did not copy the animations in the preview model to the PlacedModel and hence I modified it to do a manual copy of animations and textures. There is a function called materialize() that does this and I was able to modify it to get it working where the placed models are now animating. The issue is when I apply gestures on them like drag or rotate. For those models that go through this logic I'm unable to add gestures even though I'm making sure that Collision and Input Target is set on the Placed Models. Has anyone been able to get this working or is it even a possibility? My materialize function func materialize() -> PlacedObject { let shapes = previewEntity.components[CollisionComponent.self]!.shapes // Clone render content first as we need its materials let clonedRenderContent = renderContent.clone(recursive: true) print("To be finding main model: \(descriptor.displayName)") // Find the main model in preview hierarchy func findMainModel(_ entity: Entity) -> Entity? { if entity.name == descriptor.displayName.replacingOccurrences(of: " ", with: "_") { print("Found main model: \(entity.name)") return entity } for child in entity.children { if child.name == descriptor.displayName.replacingOccurrences(of: " ", with: "_") { print("Found main model in children: \(child.name)") return child } } return nil } // Clone hierarchy preserving structure, names, and materials func cloneHierarchy(_ entity: Entity) -> Entity { print("Cloning: \(entity.name)") let cloned: Entity if let model = entity as? ModelEntity { // Clone with recursive false to handle children manually cloned = model.clone(recursive: false) if let clonedModel = cloned as? ModelEntity, let originalMaterials = model.model?.materials { // Preserve the original model's materials clonedModel.model?.materials = originalMaterials } } else { cloned = Entity() } // Preserve name and transform cloned.name = entity.name cloned.transform = entity.transform // Clone children for child in entity.children { let clonedChild = cloneHierarchy(child) cloned.addChild(clonedChild) } return cloned } print("=== Cloning Preview Structure ===") // Clone the preview hierarchy with proper structure let clonedStructure = cloneHierarchy(previewEntity) // Find and use the main model if let mainModel = findMainModel(clonedStructure) { print("Using main model for PlacedObject") let modelEntity: ModelEntity if let asModel = mainModel as? ModelEntity { print("Using asModel ") modelEntity = asModel } else { modelEntity = ModelEntity() modelEntity.name = mainModel.name // Copy children and transforms for child in mainModel.children { modelEntity.addChild(child) } modelEntity.transform = mainModel.transform } // Add collision component here let collisionComponent = CollisionComponent(shapes: shapes, isStatic: false, filter: CollisionFilter(group: PlacedObject.collisionGroup, mask: .all)) modelEntity.components.set(collisionComponent) // Create the placed object let placedObject = PlacedObject(descriptor: descriptor, renderContentToClone: modelEntity, shapes: shapes) // Set input target on the placed object itself placedObject.components.set(InputTargetComponent(allowedInputTypes: [.direct, .indirect])) return placedObject } else { print("Fallback to original render content") let placedObject = PlacedObject(descriptor: descriptor, renderContentToClone: clonedRenderContent, shapes: shapes) placedObject.components.set(InputTargetComponent(allowedInputTypes: [.direct, .indirect])) return placedObject } } My PlacedObject class where the init has the recursive cloning removed because it is handled in materialize class PlacedObject: Entity { let fileName: String // The 3D model displayed for this object. private let renderContent: ModelEntity static let collisionGroup = CollisionGroup(rawValue: 1 << 29) // The origin of the UI attached to this object. // The UI is gravity aligned and oriented towards the user. let uiOrigin = Entity() var affectedByPhysics = false { didSet { guard affectedByPhysics != oldValue else { return } if affectedByPhysics { components[PhysicsBodyComponent.self]!.mode = .static } else { components[PhysicsBodyComponent.self]!.mode = .static } } } var isBeingDragged = false { didSet { affectedByPhysics = !isBeingDragged } } var positionAtLastReanchoringCheck: SIMD3<Float>? var atRest = false init(descriptor: ModelDescriptor, renderContentToClone: ModelEntity, shapes: [ShapeResource]) { fileName = descriptor.fileName // renderContent = renderContentToClone.clone(recursive: true) renderContent = renderContentToClone super.init() name = renderContent.name // Apply the rendered content’s scale to this parent entity to ensure // that the scale of the collision shape and physics body are correct. scale = renderContent.scale renderContent.scale = .one // Make the object respond to gravity. let physicsMaterial = PhysicsMaterialResource.generate(restitution: 0.0) let physicsBodyComponent = PhysicsBodyComponent(shapes: shapes, mass: 1.0, material: physicsMaterial, mode: .static) components.set(physicsBodyComponent) components.set(CollisionComponent(shapes: shapes, isStatic: false, filter: CollisionFilter(group: PlacedObject.collisionGroup, mask: .all))) addChild(renderContent) addChild(uiOrigin) uiOrigin.position.y = extents.y / 2 // Position the UI origin in the object’s center. // Allow direct and indirect manipulation of placed objects. components.set(InputTargetComponent(allowedInputTypes: [.direct, .indirect])) // Add a grounding shadow to placed objects. renderContent.components.set(GroundingShadowComponent(castsShadow: true)) } required init() { fatalError("`init` is unimplemented.") } } Thanks
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Feb ’25