Discuss Spatial Computing on Apple Platforms.

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Persistent Entity Position
I want to let users place 2D/3D “artworks” on detected walls and have them reappear in exactly the same real‑world spot after quitting and relaunching the app (like widgets do, but for my own entities).Environment: Xcode 26, visionOS 2.0, RealityKit + ARKitSession/WorldTrackingProvider Entities are parented to a holder that’s aligned to a wall via plane/mesh raycasts. What I’ve tried: Create a WorldAnchor at placement, save UUID + full 4×4 transform On next launch, re-create the WorldAnchor (or set the saved transform) and attach the entity Gate restore on relocalization/mesh updates and disable all raycast/search after restore Issue: After relaunch, placement still resolves relative to current device pose, not the same wall position. Questions: Is there a public API in visionOS 2.0 to persist app‑managed world anchors across sessions (room‑fixed), e.g., AnchorStore or equivalent? If not, what’s the recommended pattern to reliably restore wall‑anchored content? Are persistence features mentioned for widgets/windows available to third‑party RealityKit entities?
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Oct ’25
Immersive environment learning material
I really love the immersive environments, but I don’t have experience with creating them. Do you have resources or tutorials you can recommend for creating these from scratch? I’ve seen the sample projects and videos, but they usually start in the middle, assuming you already have the assets created.
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Jul ’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
version update in Vision Pro
Hi, I'm developing an app for Vision Pro using Xcode, while updating the latest update, things that worked in my app suddenly didn't. in my app flow I'm tapping spheres to get their positions, from some reason I get an offset from where I tap to where a marker on that position is showing up. here's the part of code that does that, and a part that is responsible for an alignment that happens afterwards: func loadMainScene(at position: SIMD3) async { guard let content = self.content else { return } do { let rootEntity = try await Entity(named: "surgery 16.09", in: realityKitContentBundle) rootEntity.scale = SIMD3<Float>(repeating: 0.5) rootEntity.generateCollisionShapes(recursive: true) self.modelRootEntity = rootEntity let bounds = rootEntity.visualBounds(relativeTo: nil) print("📏 Model bounds: center=\(bounds.center), extents=\(bounds.extents)") let pivotEntity = Entity() pivotEntity.addChild(rootEntity) self.pivotEntity = pivotEntity let modelAnchor = AnchorEntity(world: [1, 1.3, -0.8]) modelAnchor.addChild(pivotEntity) content.add(modelAnchor) updateModelOpacity(0.5) self.modelAnchor = modelAnchor rootEntity.visit { entity in print("👀 Entity in model: \(entity.name)") if entity.name.lowercased().hasPrefix("focus") { entity.generateCollisionShapes(recursive: true) entity.components.set(InputTargetComponent()) print("🎯 Made tappable: \(entity.name)") } } print("✅ Model loaded with collisions") guard let sphere = placementSphere else { return } let sphereWorldXform = sphere.transformMatrix(relativeTo: nil) var newXform = sphereWorldXform newXform.columns.3.y += 0.1 // move up by 20 cm let gridAnchor = AnchorEntity(world: newXform) self.gridAnchor = gridAnchor content.add(gridAnchor) let baseScene = try await Entity(named: "Scene", in: realityKitContentBundle) let gridSizeX = 18 let gridSizeY = 10 let gridSizeZ = 10 let spacing: Float = 0.05 let startX: Float = -Float(gridSizeX - 1) * spacing * 0.5 + 0.3 let startY: Float = -Float(gridSizeY - 1) * spacing * 0.5 - 0.1 let startZ: Float = -Float(gridSizeZ - 1) * spacing * 0.5 for i in 0..<gridSizeX { for j in 0..<gridSizeY { for k in 0..<gridSizeZ { if j < 2 || j > gridSizeY - 5 { continue } // remove 2 bottom, 4 top let cell = baseScene.clone(recursive: true) cell.name = "Sphere" cell.scale = .one * 0.02 cell.position = [ startX + Float(i) * spacing, startY + Float(j) * spacing, startZ + Float(k) * spacing ] cell.generateCollisionShapes(recursive: true) gridCells.append(cell) gridAnchor.addChild(cell) } } } content.add(gridAnchor) print("✅ Grid added") } catch { print("❌ Failed to load: \(error)") } } private func handleModelOrGridTap(_ tappedEntity: Entity) { guard let modelRootEntity = modelRootEntity else { return } let localPosition = tappedEntity.position(relativeTo: modelRootEntity) let worldPosition = tappedEntity.position(relativeTo: nil) switch tapStep { case 0: modelPointA = localPosition modelAnchor?.addChild(createMarker(at: worldPosition, color: [1, 0, 0])) print("📍 Model point A: \(localPosition)") tapStep += 1 case 1: modelPointB = localPosition modelAnchor?.addChild(createMarker(at: worldPosition, color: [1, 0.5, 0])) print("📍 Model point B: \(localPosition)") tapStep += 1 case 2: targetPointA = worldPosition targetMarkerA = createMarker(at: worldPosition,color: [0, 1, 0]) modelAnchor?.addChild(targetMarkerA!) print("✅ Target point A: \(worldPosition)") tapStep += 1 case 3: targetPointB = worldPosition targetMarkerB = createMarker(at: worldPosition,color: [0, 0, 1]) modelAnchor?.addChild(targetMarkerB!) print("✅ Target point B: \(worldPosition)") alignmentReady = true tapStep += 1 default: print("⚠️ Unexpected tap on model helper at step \(tapStep)") } } func alignModel2Points() { guard let modelPointA = modelPointA, let modelPointB = modelPointB, let targetPointA = targetPointA, let targetPointB = targetPointB, let modelRootEntity = modelRootEntity, let pivotEntity = pivotEntity, let modelAnchor = modelAnchor else { print("❌ Missing data for alignment") return } let modelVec = modelPointB - modelPointA let targetVec = targetPointB - targetPointA let modelLength = length(modelVec) let targetLength = length(targetVec) let scale = targetLength / modelLength let modelDir = normalize(modelVec) let targetDir = normalize(targetVec) var axis = cross(modelDir, targetDir) let axisLength = length(axis) var rotation = simd_quatf() if axisLength < 1e-6 { if dot(modelDir, targetDir) > 0 { rotation = simd_quatf(angle: 0, axis: [0,1,0]) } else { let up: SIMD3<Float> = [0,1,0] axis = cross(modelDir, up) if length(axis) < 1e-6 { axis = cross(modelDir, [1,0,0]) } rotation = simd_quatf(angle: .pi, axis: normalize(axis)) } } else { let dotProduct = dot(modelDir, targetDir) let clampedDot = max(-1.0, min(dotProduct, 1.0)) let angle = acos(clampedDot) rotation = simd_quatf(angle: angle, axis: normalize(axis)) } modelRootEntity.scale = .one * scale modelRootEntity.orientation = rotation let transformedPointA = rotation.act(modelPointA * scale) pivotEntity.position = -transformedPointA modelAnchor.position = targetPointA alignedModelPosition = modelAnchor.position print("✅ Aligned with scale \(scale), rotation \(rotation)")
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Oct ’25
How to play blend shape animations or morph animations exported from blender in Vision Pro apps using Reality Kit
So I am exporting a .usdc file from blender that already has some morph animations. The animations play well in blender but when I export I cannot seem to play them in RealityKit or RCP. Entity.availableAnimations is an empty array. Not of the child objects in the entity hierarchy has an animation library component with it. Maybe I am exporting it wrong but I tried multiple combinations but doesn't seem to work. Here are my export settings in blender The original file I purchased is an FBX file that has the animation but when I try to directly get it in RealityConverter it doesn't seem to play animations.
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Jun ’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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684
Feb ’25
How to request several models simultaneously
I am using HelloPhotogrammetry in Xcode I can make one model with something like HelloPhotogrammetry.main([path_to_folder_of images, path_to_output/model.usdz, "-d", "medium", "-o", "unordered", "-f", "high" ]) But how would I request several models simultaneously? I only want to vary the detail. [ ("/Users/you/Desktop/model_medium.usdz", detail: .medium), ("/Users/you/Desktop/model_full.usdz", detail: .full), ("/Users/you/Desktop/model_raw.usdz", detail: .raw ]
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Apr ’25
Metal Compositor Service & Persona (VisionOS)
Hello, I'm currently trying to make a collaborative app. But it just works only on Reality View, when I tried to use Compositor Layer like below, the personas disappeared. ImmersiveSpace(id: "ImmersiveSpace-Metal") { CompositorLayer(configuration: MetalLayerConfiguration()) { layerRenderer in SpatialRenderer_InitAndRun(layerRenderer) } } Is there any potential solution too see Personas in Metal view? Thanks in advance!
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756
Sep ’25
Converting a Stop Motion Animation to usdz
Hello everyone, I've been trying for a few weeks now to convert a sequential series of meshes into a stop-motion animation in USDZ format. In Unreal Engine, I’ve already figured out how to transform the sequential series of individual meshes into a smooth animation using the node system and arrays. Unfortunately, the node system cannot be exported as a usdz animation logic in either Unreal or Blender. Because of this, I have tried several other methods to incorporate the animation logic. Here’s what I’ve tried so far: I attempted to create the animation in Blender with Render-/Viewports and mapping it to keyframes. However, in my experience, Viewports are not supported in the conversion. I tried aligning the vertices of individual objects and merging the frames using the Shrinkwrap modifier in Blender, then setting up a morph animation with keyframes. However, because the individual meshes are too different, this results in artifacts, and manually editing each mesh is too difficult for me to handle. I placed all individual meshes at the same position and animated them sequentially by scaling them from 0 to 100 in keyframes (Frame 1 is visible for 10 frames, then scales down at frame 11, while Frame 2 becomes visible at frame 11, and so on). I also adjusted the keyframes so that the scaling happens in a "constant" manner rather than the default Bezier or linear interpolation. I then converted this animation to .abc, and the result initially looked good. However, some information is lost when converting it with OpenUSD. The animation does not maintain its intended jump-like behavior in USDZ format, and instead, the scaling of individual files is visible in the animation. I tried using a Blender add-on (StepMotion), which allows the animation to be exported as .abc, but it can only be read in Blender or Unreal. Even in the preview, the animation is not displayed correctly, so converting the animation logic does not work either. 
Unfortunately, I have no alternative way to create the animation, as the individual frames have been provided to me as meshes. So far, I haven’t found a way to implement this successfully. I would be very grateful for any tips or ideas, as I am running out of options on how to make this work. Thanks in advance!
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193
Apr ’25
Performance drop when particle emitter is combined with video play
Hi All, We're a studio building an app and as part of a scene we have a 3D asset with a smoke particle emitter and a curved mesh that plays video. I notice that when the video alone is played or the particle effect alone is done then the scene works fine but the frame rate drops drastically when both are turned on. How do I solve this because this is an important storytelling feature.
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311
Oct ’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
Getting the world position of a QR code
Hi, would love for your help in that matter. I try to get the position in space of two QR codes to make an alignment to their positions in space. The detection shows that the QR codes position is always 0,0,0 and I don't understand why. Here's my code: import SwiftUI import RealityKit import RealityKitContent struct AnchorView: View { @ObservedObject var qrCoordinator: QRCoordinator @ObservedObject var coordinator: ImmersiveCoordinator let qrName: String @Binding var startQRDetection: Bool @State private var anchor: AnchorEntity? = nil @State private var detectionTask: Task<Void, Never>? = nil var body: some View { RealityView { content in // Add the QR anchor once (must exist before detection starts) if anchor == nil { let imageAnchor = AnchorEntity(.image(group: "QRs", name: qrName)) content.add(imageAnchor) anchor = imageAnchor print("📌 Created anchor for \(qrName)") } } .onChange(of: startQRDetection) { enabled in if enabled { startDetection() } else { stopDetection() } } .onDisappear { stopDetection() } } private func startDetection() { guard detectionTask == nil, let anchor = anchor else { return } detectionTask = Task { var detected = false while !Task.isCancelled && !detected { print("🔎 Checking \(qrName)... isAnchored=\(anchor.isAnchored)") if anchor.isAnchored { // wait a short moment to let transform update try? await Task.sleep(nanoseconds: 100_000_000) let worldPos = anchor.position(relativeTo: nil) if worldPos != .zero { // relative to modelRootEntity if available var posToSave = worldPos if let modelEntity = coordinator.modelRootEntity { posToSave = anchor.position(relativeTo: modelEntity) print("converted to model position") } else { print("⚠️ modelRootEntity not available, using world position") } print("✅ \(qrName) detected at position: world=\(worldPos) saved=\(posToSave)") if qrName == "reanchor1" { qrCoordinator.qr1Position = posToSave let marker = createMarker(color: [0,1,0]) marker.position = .zero // sits directly on QR marker.position = SIMD3<Float>(0, 0.02, 0) anchor.addChild(marker) print("marker1 added") } else if qrName == "reanchor2" { qrCoordinator.qr2Position = posToSave let marker = createMarker(color: [0,0,1]) marker.position = posToSave // sits directly on QR marker.position = SIMD3<Float>(0, 0.02, 0) anchor.addChild(marker) print("marker2 added") } detected = true } else { print("⚠️ \(qrName) anchored but still at origin, retrying...") } } try? await Task.sleep(nanoseconds: 500_000_000) // throttle loop } print("🛑 QR detection loop ended for \(qrName)") detectionTask = nil } } private func stopDetection() { detectionTask?.cancel() detectionTask = nil } private func createMarker(color: SIMD3<Float>) -> ModelEntity { let sphere = MeshResource.generateSphere(radius: 0.05) let material = SimpleMaterial(color: UIColor( red: CGFloat(color.x), green: CGFloat(color.y), blue: CGFloat(color.z), alpha: 1.0 ), isMetallic: false) let marker = ModelEntity(mesh: sphere, materials: [material]) marker.name = "marker" return marker } }
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491
Oct ’25