Discuss spatial computing on Apple platforms and how to design and build an entirely new universe of apps and games for Apple Vision Pro.

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目前在使用Unity进行开发时,遇到了材质(Material)和Shader在visionOS设备上无法正常渲染的问题
具体表现为:在Unity编辑器中材质显示正常,但部署到Vision Pro真机后部分材质丢失或Shader效果异常(如透明通道失效、光照计算错误等)。此问题影响了开发进度,希望得到技术支持的帮助 Specific results: The materials are displayed normally in the Unity editor, but after being deployed to the Vision Pro real machine, some materials are lost or the Shader effect is abnormal (such as transparent channel failure, antenna calculation error, etc.). This problem has affected the development progress, and I hope to get help from technical support
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Apr ’25
What is the first reliable position of the apple vision pro device?
In several visionOS apps, we readjust our scenes to the user's eye level (their heads). But, we have encountered issues whereby the WorldTrackingProvider returns bad/incorrect positions for the first x number of frames. See below code which you can copy paste in any Immersive Space. Relaunch the space and observe the numberOfBadWorldInfos value is inconsistent. a. what is the most reliable way to get the devices's position? b. is this indeed a bug? c. are we using worldInfo improperly? d. as a workaround, in our apps we set to 10 the number of frames to let pass before using worldInfo, should we set our threshold differently? import ARKit import Combine import OSLog import SwiftUI import RealityKit import RealityKitContent let SUBSYSTEM = Bundle.main.bundleIdentifier! struct ImmersiveView: View { let logger = Logger(subsystem: SUBSYSTEM, category: "ImmersiveView") let session = ARKitSession() let worldInfo = WorldTrackingProvider() @State var sceneUpdateSubscription: EventSubscription? = nil @State var deviceTransform: simd_float4x4? = nil @State var numberOfBadWorldInfos = 0 @State var isBadWorldInfoLoged = false var body: some View { RealityView { content in try? await session.run([worldInfo]) sceneUpdateSubscription = content.subscribe(to: SceneEvents.Update.self) { event in guard let pose = worldInfo.queryDeviceAnchor(atTimestamp: CACurrentMediaTime()) else { return } // `worldInfo` does not return correct values for the first few frames (exact number of frames is unknown) // - known SO: https://stackoverflow.com/questions/78396187/how-to-determine-the-first-reliable-position-of-the-apple-vision-pro-device deviceTransform = pose.originFromAnchorTransform if deviceTransform!.columns.3.y < 1.6 { numberOfBadWorldInfos += 1 logger.warning("\(#function) \(#line) deviceTransform.columns.3.y \(deviceTransform!.columns.3.y), numberOfBadWorldInfos \(numberOfBadWorldInfos)") } else { if !isBadWorldInfoLoged { logger.info("\(#function) \(#line) deviceTransform.columns.3.y \(deviceTransform!.columns.3.y), numberOfBadWorldInfos \(numberOfBadWorldInfos)") } isBadWorldInfoLoged = true // stop logging. } } } } }
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Apr ’25
RealityKit System update and timing
Hi, I'm playing now with hand tracking. I want to get position of hand inside a system update function. I was not sure if transform I'm getting from hand attached AnchorEntity (with trackingMode: .predicted) would give same results as handAnchors(at:) from hand tracking provider, so I started to read them both and compare. For handAnchors i tried using context.scene.timebase.sourceTimebase!.sourceClock!.time.seconds and CACurrentMediaTime() as timestamp source. They seem to use exactly same clock, so that doesn't matter, but: for some reason update handler is always called twice with same context.deltaTime, but first time the query finds 0 entities, second time it finds them all. The query is the standard EntityQuery(where: .has(MyComponent.self)) and in update (matching: Self.query, updatingSystemWhen: .rendering). Here's part of logs: System update called, entity count: 0, dt: 0.01000458374619484, absTime: 4654.222593541 System update called, entity count: 11, dt: 0.01000458374619484, absTime: 4654.22262525 System update called, entity count: 0, dt: 0.009999999776482582, absTime: 4654.249390875 System update called, entity count: 11, dt: 0.009999999776482582, absTime: 4654.249425 accounting for the double update calling I started to calculate time delta of absolute time between calls and they're most of the time much bigger, or much smaller than advertised by system's context.deltaTime, only sometimes they kind of match, for example: system: (dt: 0.01000458374619484) scene : (dt: 0.021419291667371) (absTime: 4654.222628125001) and the very next call system: (dt: 0.010009 166784584522) scene : (dt: 0.0013097083328830195) (absTime: 4654.223937833334) but sometimes system: (dt: 0.009999999776482582) scene : (dt: 0.009 112249999816413) (absTime: 4654.351299 166668) Shouldn't those be more or less equal, or am I missing something? In the end it seems that getting hand position from AnchorEntity and with handAnchors(at:) gives kind of same results, but at different time points, so I'd love to understand what's the correct way to use them and why time flows differently :). --Edit-- P.S. Had to put spaces everywhere in logs between "9" and "1", otherwise post was blocked due to "sensitive content" :D
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Apr ’25
How to Achieve Realistic Colors and Textures in LiDAR Scanning with Swift
Hello, I'm developing a LiDAR-based scanning app using Swift, where I can successfully perform scans and export the results as .obj files. My goal is to have the scan's colors and textures closely resemble real-world visuals as captured by the camera, similar to the results shown in this repository. In the referenced repository, the result is demonstrated with a single screenshot, but I want to display the textures and colors throughout the entire scanning process, not just at the final result. To clarify, I'm not focused on scanning individual objects but rather larger environments like rooms, houses, or outdoor spaces such as streets. Here’s what I’m aiming for: Realistic colors and textures that match what the camera sees during the scan. Continuous texture rendering during the scanning process, not just in the final exported model. Could anyone share guidance, sample code, or point me to relevant documentation to achieve this? Any help would be greatly appreciated! Thank you!
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Apr ’25
Cursor display issue on attachment view in immersive space
While using Screen Mirroring in developer mode within my immersive space, I noticed an alignment issue with the computer cursor (transparent circle). When I move it toward an attachment view, the cursor remains horizontal instead of aligning with the surface of the attachment view. It shows correctly on a 2D window only wrong on attachment view. Is this behavior a bug, or could it be caused by a missing or incorrect configuration on the attachment view? Want help, thanks.
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Apr ’25
RoomPlan crash on iOS 16 devices even when using available checks
I've encountered an unexpected crash with RoomPlan on iOS 16 devices. The odd part is the code is protected by an available check, since I'm using newer RoomPlan features. Xcode error dyld[40588]: Symbol not found: _$s8RoomPlan08CapturedA0V16USDExportOptionsV5modelAEvgZ I can repro using the Apple sample code. https://developer.apple.com/documentation/roomplan/create-a-3d-model-of-an-interior-room-by-guiding-the-user-through-an-ar-experience Modify RoomCaptureViewController.swift as follows. Remove try finalResults?.export(to: destinationURL, exportOptions: .parametric) Add if #available(iOS 17.0, *) { try finalResults?.export(to: destinationURL, exportOptions: .model) } else { try finalResults?.export(to: destinationURL, exportOptions: .parametric) } I would have expected this code to at least compile and run on older devices. When the app was targeting iOS 15, the available checks worked as expected and the app is able to launch properly.
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Apr ’25
Summon gesture
Can you help to write a code able to pick an element a bit far from me, then bring it near to me, flick it a bit and then send it back to its original position when I release it? Thanks a lot, Christophe
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Apr ’25
Depth matrix accuracy with the iPhone 14 Pro and Lidar
Hello Community, I’m currently working with the sample code “CapturingDepthUsingTheLiDARCamera” and using it to capture the depth map of an image taken with the iPhone 14 Pro. From this depth map, I generate a point cloud using the intrinsic camera parameters. I've noticed that objects not facing the camera directly appear distorted in the resulting point cloud. For example: An object with surfaces that are perpendicular to each other appears with a sharper angle in the point cloud — around 60° instead of 90°. My question is: Is this due to the general accuracy limitations of the LiDAR sensor? Or could it be related to the sample code? To obtain the depth map, I’m using: AVCapturePhoto.depthData.converting(toDepthDataType: kCVPixelFormatType_DepthFloat32) Thanks in advance for your help!
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Apr ’25
Partial Occlusion Material
I am looking for a material that functions in the same way that Occlusion Material does, except that it only partially occludes whatever is behind it. One way that I have thought of doing this was to change the opacity of the entity that was covered in Occlusion Material, however this did not change anything. Please let me know if this is possible.
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Apr ’25
Apply mesh to real world people.
As far as I know, Apple hasn’t opened access to the Vision Pro camera for developers yet, so I’m trying to find possible workarounds within the current capabilities. I’m wondering if there’s any way to apply a mesh to a person in the scene in Vision Pro, or if there’s an alternative approach to roughly detect a human shape in front of the user?
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Apr ’25
ARKit Planes do not appear where expected on visionOS
I'm using ARKitSession and PlaneDetectionProvider to detect planes. I have a basics process to create an entity for each detected plane. Each one will get a random color for the material. Each plane is sized based on the bounds of the anchor provided by ARKit. let mesh = MeshResource.generatePlane( width: anchor.geometry.extent.width, depth: anchor.geometry.extent.height ) Then I'm using this to position each entity. entity.transform = Transform(matrix: anchor.originFromAnchorTransform) This seems to be the right method, but many (not all) planes are not where they should be. The sizes look OK, but the X and Y positions off. Take this large green plane on the wall. It should span the entire wall, but it is offset along the X position so that it is pushed to the left from where the center of the anchor is. When I visualize surfaces using the Xcode debugging tools, that tool reports the planes where I'd expect them to be. Can you see what I'm getting wrong here? Full code below struct Example068: View { @State var session = ARKitSession() @State private var planeAnchors: [UUID: Entity] = [:] @State private var planeColors: [UUID: Color] = [:] var body: some View { RealityView { content in } update: { content in for (_, entity) in planeAnchors { if !content.entities.contains(entity) { content.add(entity) } } } .task { try! await setupAndRunPlaneDetection() } } func setupAndRunPlaneDetection() async throws { let planeData = PlaneDetectionProvider(alignments: [.horizontal, .vertical, .slanted]) if PlaneDetectionProvider.isSupported { do { try await session.run([planeData]) for await update in planeData.anchorUpdates { switch update.event { case .added, .updated: let anchor = update.anchor if planeColors[anchor.id] == nil { planeColors[anchor.id] = generatePastelColor() } let planeEntity = createPlaneEntity(for: anchor, color: planeColors[anchor.id]!) planeAnchors[anchor.id] = planeEntity case .removed: let anchor = update.anchor planeAnchors.removeValue(forKey: anchor.id) planeColors.removeValue(forKey: anchor.id) } } } catch { print("ARKit session error \(error)") } } } private func generatePastelColor() -> Color { let hue = Double.random(in: 0...1) let saturation = Double.random(in: 0.2...0.4) let brightness = Double.random(in: 0.8...1.0) return Color(hue: hue, saturation: saturation, brightness: brightness) } private func createPlaneEntity(for anchor: PlaneAnchor, color: Color) -> Entity { let mesh = MeshResource.generatePlane( width: anchor.geometry.extent.width, depth: anchor.geometry.extent.height ) var material = PhysicallyBasedMaterial() material.baseColor.tint = UIColor(color) let entity = ModelEntity(mesh: mesh, materials: [material]) entity.transform = Transform(matrix: anchor.originFromAnchorTransform) return entity } }
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Apr ’25
VisionPro camera frame rate
Hi, I'm working with CameraFrameProvider from Enterprise API. Is it always capped at 30fps, or is there something I can switch to get more? I assume it is capped at 30, so let me cram in additional question here :). If I'd get a developer strap and attach an external camera capable of doing >30fps, will I get the full stream, or some other limitation will kick in?
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Apr ’25
how to achieve "concave in" glass view look?
I have been trying to implement this look where a component looks "pushed in" but I could not find any resources regarding this effect. The closest I got was a combination of a RoundedRectangle and .glassBackgroundEffect(), but this makes the view look pushed out, instead of pushed in. I was wondering if this is achievable in SwiftUI level, or even in UIKit level.
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Apr ’25
Spaceship sample code does not compile
I'm getting the following error message when compiling the Apple provided sample, Spaceship game for the Apple Visio Pro. I've already tried deleting the derived data resetting the package cache and restarting Xcode but still getting the following error: [xrsimulator] Exception thrown during compile: Cannot get rkassets content for path /Users/myoungkang/Downloads/CreatingASpaceshipGame/Packages/Studio/Sources/Studio/Studio.rkassets because 'The file “Studio.rkassets” couldn’t be opened because you don’t have permission to view it.' error: Tool exited with code 1
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Apr ’25
How to create a MultiplayerDelegate and use TabletopNetworkSession features?
When building a multiplayer Tabletop game, the documentation includes how to attach a custom TabletopNetworkSessionCoordinator, which could be used in addition to TabletopGame.MultiplayerDelegate. But so far, we have been unable to create these types of custom coordinators or have a delegate that works. Our current setup with our generic GroupActivity works by sending the session to TabletopGame's coordinateWithSession method (like in the current sample project), but we didn't find a way to access and control, for example, the arbiter, seats, player events, among other features mentioned on https://developer.apple.com/documentation/tabletopkit/tabletopnetworksession. Is correct to expect having access to the participants, messenger, or journal without having to maintain a parallel coordinator?   possibly we are missing something here; any suggestions?
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Apr ’25