Discuss Spatial Computing on Apple Platforms.

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How to show only Spatial video using UIDocumentPickerViewController
Is there a suitable UTType type to satisfy the need to pick up only SpatialVideo in UIDocumentPickerViewController? I already know that PHPickerFilter in PHPickerViewController can do this, but not in UIDocumentPickerViewController. Our app needs to adapt both of these ways to pick spatial videos So is there anything that I can try in UIDocumentPickerViewController to fulfill such picker functionality?
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Feb ’25
Body segmentation/occlusion on the Apple Vision Pro
Hello, I am currently working on a Unity project for the Apple Vision Pro. I would like to have people passing in front of the virtual objects occlude the virtual objects that are behind. Something similar to this: https://developer.apple.com/documentation/arkit/occluding-virtual-content-with-people I could unfortunately not find any documentation about this. Is it possible to implement body segmentation or occlusion on the Apple Vision Pro? If it's not currently supported, are there plans to add it? Any ideas on how to achieve this with existing tools? Thanks! Mehdi
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Feb ’25
Reading scenePhase from custom Scene
Hi, I've encountered a thread where an Apple engineer points out that there are 2 possible ways to anchor scenePhase, either App or View implementation: https://developer.apple.com/forums/thread/757429 This thread also links to documentation which states If you read the phase from within a custom Scene instance, the value similarly reflects an aggregation of all the scenes that make up the custom scene: This doesn't seem to be the case on visionOS 2, I tried the following code starting from an empty app template: import SwiftUI @main struct SceneTestApp: App { var body: some Scene { MyScene() WindowGroup(id: "extra") { Text("Extra window") } } } struct MyScene: Scene { @Environment(\.scenePhase) private var scenePhase @Environment(\.openWindow) private var openWindow var body: some Scene { WindowGroup { ContentView() .onAppear { openWindow(id: "extra") } } .onChange(of: scenePhase) { oldValue, newValue in print("scenePhase changed") } } } The result was that I didn't get onChange callback if I only closed the extra window, the callback only came after I closed both windows and the whole app was suspended. Is this expected behavior?
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Feb ’25
WorldTrackingProvider stops working on device
After re-launching the immersive space in my app 5-10 times, the WorldTrackingProvider stops working. Only restarting the app will allow it to start working again. Only on device, not the simulator. I get these errors when it happens: The device_anchor can only be queried when the world tracking provider is running. ARPredictorRemoteService <0x107cbb5e0>: Service configured with error: Error Domain=com.apple.arkit.error Code=501 "(null)" Remote Service was invalidated: <ARPredictorRemoteService: 0x107cbb5e0>, will stop all data_providers. ARRemoteService: remote object proxy failed with error: Error Domain=NSCocoaErrorDomain Code=4099 "The connection to service with pid 81 named com.apple.arkit.service.session was invalidated from this process." UserInfo={NSDebugDescription=The connection to service with pid 81 named com.apple.arkit.service.session was invalidated from this process.} ARRemoteService: weak self released before invalidation @Observable class VisionPro { let session = ARKitSession() let worldTracking = WorldTrackingProvider() func transformMatrix() async -> simd_float4x4 { guard let deviceAnchor = worldTracking.queryDeviceAnchor(atTimestamp: CACurrentMediaTime()) else { return .init() } return deviceAnchor.originFromAnchorTransform } func runArkitSession() async { Task { try? await session.run([worldTracking]) } } } which I call from my RealityView: .task { await visionPro.runArkitSession() }
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Feb ’25
Building a custom render pipeline with RealityKit
Hello experts, and question seekers, I have been trying to get Gaussian splats working with RealityKit, however it seems not to work out for me. The library I use for Gaussian splatting: https://github.com/scier/MetalSplatter My idea was to use the renderers provided by RealityKit (aka RealityRenderer) https://developer.apple.com/documentation/realitykit/realityrenderer and the renderer provided by MetalSplatter (aka. SplatRenderer) https://github.com/scier/MetalSplatter/blob/main/MetalSplatter/Sources/SplatRenderer.swift Then with a custom render pipeline, I would be able to compose the outputs of the renderers, enabling the possibility, for example to build immersive scenery with realistic environment scans, as Gaussian splats, and RealityKit to provide the necessary features to build extra scenery around Gaussian splats, eg. dynamic 3D models inside Gaussian splats. However the problem is, as of now I am not able to do that with the current implementation of RealityRenderer. It seems to be, that first RealityRenderer is supposed to be an API, just to render colour information onto a texture, which in first glance might be useful, but misses important information, such as for example depth, and stencil information. Second issue is, even with that in mind, currently I am not able to execute RealityRenderer.updateAndRender, due to the following error messages: Could not resolve material name 'engine:BuiltinRenderGraphResources/Common/realityRendererBackground.rematerial' in bundle at '/Users//Library/Developer/CoreSimulator/Devices//data/Containers/Bundle/Application//.app'. Loading via asset path. exiting spatial tracking service update thread because wait returned 37” I was able to build a custom Metal view with UIViewRepresentable, MTKView, and MTKViewDelegate, enabling me to build a custom rendering pipeline, by utilising some of the Metal developer workflows. Reference: https://developer.apple.com/documentation/xcode/metal-developer-workflows/ Inside draw(in view: MTKView), in a class derived by MTKViewDelegate: guard let currentDrawable = view.currentDrawable else { return } let realityRenderer = try! RealityRenderer() try! realityRenderer.updateAndRender(deltaTime: 0.0, cameraOutput: .init(.singleProjection(colorTexture: currentDrawable.texture)), whenScheduled: { realityRenderer in print("Rendering scheduled") }, onComplete: { RealityRenderer in print("Rendering completed") }) Can you please tell me, what I am doing wrong? Is there any solution, that enables me to use RealityKit with for example Gaussian splats? Any help is greatly appreciated. All the best, Ethem Kurt
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Feb ’25
Setting clip shape of a RealityView
I am following this example to create a stereoscopic image: https://developer.apple.com/documentation/visionos/creating-stereoscopic-image-in-visionos I would also like to add corner radius to the stereoscopic RealityView. With ordinary SwiftUI views, we typically just use .clipShape(RoundedRectangle(cornerRadius: 32)): struct StereoImage: View { var body: some View { let spacing: CGFloat = 10.0 let padding: CGFloat = 40.0 VStack(spacing: spacing) { Text("Stereoscopic Image Example") .font(.largeTitle) RealityView { content in let creator = StereoImageCreator() guard let entity = await creator.createImageEntity() else { print("Failed to create the stereoscopic image entity.") return } content.add(entity) } .frame(depth: .zero) } .padding(padding) .clipShape(RoundedRectangle(cornerRadius: 32)) // <= HERE! } } This doesn't seem to actually clip the RealityView shown in the sample above. I am guessing this is due to the fact that the box in the RealityView has a non-zero z scale, which means it isn't on the same "layer" as its SwiftUI containers, and thus isn't clipped by the modifiers apply to the containers. How can I properly apply a clipshape to RealityViews like this? Thanks!
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Feb ’25
How to move a camera in immersive space and render its output on 2D window using RealityKit
I'm trying to develop an immersive visionOS app, which you can move an Entity having a PerspectiveCamera as its child in immersive space, and render the camera view on 2D window. According to this thread, this seems to can be achieved using RealityRenderer. But when I added the scene entity loaded from realityKitContentBundle to realityRenderer.entities, I needed to clone all entities of the scene, otherwise all entities in the immersive space will disappear. @Observable @MainActor final class OffscreenRenderModel { private let renderer: RealityRenderer private let colorTexture: MTLTexture init(scene: Entity) throws { renderer = try RealityRenderer() // If not clone entities in the scene, all entities in the immersive space will disappear renderer.entities.append(scene.clone(recursive: true)) let camera = PerspectiveCamera() renderer.activeCamera = camera renderer.entities.append(camera) ... } } Is this the expected behavior? Or is there any other way to do this (move camera in immersive space and render its output on 2D window)? Here is my sample code: https://github.com/TAATHub/RealityKitPerspectiveCamera
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Feb ’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
How to trigger other effects using hoverEffect?
I’m facing an issue while using CustomHoverEffect. In my view, there is a long title, which causes the title to be truncated. When the user hovers over it, the title should scroll. Although I have already implemented the scrolling effect, I am unsure how to trigger the scroll on hover. How should I approach this?
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Feb ’25
How to prevent system windows occlusion when using OcclusionMaterial
We use SceneReconstructionProvider to detect meshes in the surrounding environment and apply an OcclusionMaterial to them. // Assuming `entity` represents one of the detected mesh in the environment entity.components.set(ModelComponent( mesh: mesh, materials: [OcclusionMaterial()] )) While this correctly occludes entities placed in the immersive space, it also occludes system windows. This becomes problematic when a window is dragged into an occluded area (before or after entering the immersive space), preventing interaction with its elements. In some cases, it also makes it impossible to focus on the window’s drag handle, since this might become occluded as well after moving the window nearby. More generally, system windows can be occluded when they come into proximity with a model that has OcclusionMaterial applied. I'm aware of a change introduced in visionOS 2 regarding how occlusions interact with UI elements (as noted in the release notes). I believe this change was intended to ensure windows do not remain visible when opened in another room. However, this also introduces some challenges, as described in the scenario above. Is there a way to prevent system window occlusion while still allowing entities to be occluded by environmental features? Perhaps not using OcclusionMaterial at all? Development environment: Xcode 16.2, macOS 15.2 Run-time configuration: visionOS 2.2 and 2.3
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Feb ’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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Feb ’25
Force quit apps on Vision Pro simulator
How do you force quit apps on the Vision Pro simulator? I've read online you can double press the digital crown on a real Vision Pro device but there is no such button on the simulator. So far I've tried Pressing the home button twice (⇧⌘H) Pressing the Siri button twice (⌥⇧⌘H) None of them works I'm on Xcode 15.0 beta 5 (15A5209g) &amp; visionOS 1.0 beta 2 (21N5207e)
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3.0k
Feb ’25
RoomCaptureSession with ARSCNView crashes when scanning multiple hotspots across different rooms
We're developing an iOS application that integrates RoomCaptureSession with ARSCNView for room scanning. Our implementation differs from the standard RoomCaptureView because we need custom UI guidance with 3D dots placed in the scanning environment to guide users through the capture process. Bug Description: The application crashes when users attempt to scan multiple rooms or apartments in sequence. The crash specifically occurs with the following pattern: User successfully scans first room with multiple hotspots (working correctly) User stops scanning, moves to a new room In the new room, first 1-2 hotspots work correctly Application crashes when attempting to scan additional hotspots Technical Details: Error: SLAM Anchor assertion failure in SlamAnchor.cpp:37 : HasValidPose() Crash occurs in Thread 27 with CAPIDetectionOutputFwdNode Error suggests invalid positioning when placing AR anchors Steps to Reproduce: Start room scan Complete multiple hotspot captures in first room Stop scanning Start new room scan Capture 1-2 hotspots successfully Attempt additional hotspot captures -> crashes Attempted Solutions: Implemented anchor cleanup between sessions Added position validation before anchor placement Implemented ARSession error handling Added proper thread management for AR operations Environment: Device: iPhone 14 Pro (LiDAR equipped) iOS Version: 18.1.1 (22B91) Testing through TestFlight Crash Log Details: Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Exception Note: EXC_CORPSE_NOTIFY Triggered by Thread: 27 Thread 27 Crashed: 0 libsystem_kernel.dylib 0x00000001f0cc91d4 __pthread_kill + 8 1 libsystem_pthread.dylib 0x0000000228e12ef8 pthread_kill + 268 2 libsystem_c.dylib 0x00000001a86bbad8 abort + 128 3 AppleCV3D 0x0000000234d71a28 cv3d::vio::capi::SlamAnchor::SlamAnchor Question: Is there a recommended approach for handling multiple room captures with custom ARSCNView integration? The standard RoomCaptureView implementation doesn't show this behavior, but we need the custom guidance functionality that ARSCNView provides. Crash Log Code and full crash logs can be provided if needed.
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Feb ’25
Unexpected Behavior in Entity Movement System When Using AVAudioPlayer in visionOS Development
I am currently developing an app for visionOS and have encountered an issue involving a component and system that moves an entity up and down within a specific Y-axis range. The system works as expected until I introduce sound playback using AVAudioPlayer. Whenever I use AVAudioPlayer to play sound, the entity exhibits unexpected behaviors, such as freezing or becoming unresponsive. The freezing of the entity's movement is particularly noticeable when playing the audio for the first time. After that, it becomes less noticeable, but you can still feel it, especially when the audio is played in quick succession. Also, the issue is more noticable on real device than the simulator // // IssueApp.swift // Issue // // Created by Zhendong Chen on 2/1/25. // import SwiftUI @main struct IssueApp: App { var body: some Scene { WindowGroup { ContentView() } .windowStyle(.volumetric) } } // // ContentView.swift // Issue // // Created by Zhendong Chen on 2/1/25. // import SwiftUI import RealityKit import RealityKitContent struct ContentView: View { @State var enlarge = false var body: some View { RealityView { content, attachments in // Add the initial RealityKit content if let scene = try? await Entity(named: "Scene", in: realityKitContentBundle) { if let sphere = scene.findEntity(named: "Sphere") { sphere.components.set(UpAndDownComponent(speed: 0.03, minY: -0.05, maxY: 0.05)) } if let button = attachments.entity(for: "Button") { button.position.y -= 0.3 scene.addChild(button) } content.add(scene) } } attachments: { Attachment(id: "Button") { VStack { Button { SoundManager.instance.playSound(filePath: "apple_en") } label: { Text("Play audio") } .animation(.none, value: 0) .fontWeight(.semibold) } .padding() .glassBackgroundEffect() } } .onAppear { UpAndDownSystem.registerSystem() } } } // // SoundManager.swift // LinguaBubble // // Created by Zhendong Chen on 1/14/25. // import Foundation import AVFoundation class SoundManager { static let instance = SoundManager() private var audioPlayer: AVAudioPlayer? func playSound(filePath: String) { guard let url = Bundle.main.url(forResource: filePath, withExtension: ".mp3") else { return } do { audioPlayer = try AVAudioPlayer(contentsOf: url) audioPlayer?.play() } catch let error { print("Error playing sound. \(error.localizedDescription)") } } } // // UpAndDownComponent+System.swift // Issue // // Created by Zhendong Chen on 2/1/25. // import RealityKit struct UpAndDownComponent: Component { var speed: Float var axis: SIMD3<Float> var minY: Float var maxY: Float var direction: Float = 1.0 // 1 for up, -1 for down var initialY: Float? init(speed: Float = 1.0, axis: SIMD3<Float> = [0, 1, 0], minY: Float = 0.0, maxY: Float = 1.0) { self.speed = speed self.axis = axis self.minY = minY self.maxY = maxY } } struct UpAndDownSystem: System { static let query = EntityQuery(where: .has(UpAndDownComponent.self)) init(scene: RealityKit.Scene) {} func update(context: SceneUpdateContext) { let deltaTime = Float(context.deltaTime) // Time between frames for entity in context.entities(matching: Self.query, updatingSystemWhen: .rendering) { guard var component: UpAndDownComponent = entity.components[UpAndDownComponent.self] else { continue } // Ensure we have the initial Y value set if component.initialY == nil { component.initialY = entity.transform.translation.y } // Calculate the current position let currentY = entity.transform.translation.y // Move the entity up or down let newY = currentY + (component.speed * component.direction * deltaTime) // If the entity moves out of the allowed range, reverse the direction if newY >= component.initialY! + component.maxY { component.direction = -1.0 // Move down } else if newY <= component.initialY! + component.minY { component.direction = 1.0 // Move up } // Apply the new position entity.transform.translation = SIMD3<Float>(entity.transform.translation.x, newY, entity.transform.translation.z) // Update the component with the new direction entity.components[UpAndDownComponent.self] = component } } } Could someone help me with this?
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Feb ’25