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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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
How to trigger actions by OnCollision in Behaviors Component
It's all about notifications to trigger actions from RCP's new Timeline system. From Compose interactive 3D content in Reality Composer Pro I am actually starting to confuse why there was need to use Entity.applyTapForBehaviors in code to trigger content in Behaviors Component. Simply because in Behaviors Component, we have chosen OnTap to allow a "Tap Notification" to trigger our action (on a selected target object). Then I guess by selecting OnCollision this trigger, I should write something like CollisionEvent.entityA.applyCollisionForBehaviors, which we don't have. And ofc the collision on my object won't trigger this action (because I only did things in RCP not in code). Ignoring this post has pointed out we could use Behaviors Component's OnNotification to trigger something for now. I found that I could still use OnTap trigger but actually put my code Entity.applyTapForBehaviors under my subscribed collision's begin event. That actually works better than OnCollision So what is the design principles here? And how could I trigger a collision notification to let my Behaviors Component's OnCollision actually works?
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654
Mar ’25
ARKit hand tracking
Hello, I am developing a visionOS application and am interested in obtaining detailed data of users’ hands through ARKit, including but not limited to Transform and rotation angle. I have reviewed Happy Beem, but it appears to only introduce the method of identifying the user’s specific gestures. Could you please advise on how to obtain the Transform and rotation angle of the user’s hand? Thank you.
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547
Mar ’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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85
Jul ’25
Can not remove final World Anchor
I’ve been having some issues removing anchors. I can add anchors with no issue. They will be there the next time I run the scene. I can also get updates when ARKit sends them. I can remove anchors, but not all the time. The method I’m using is to call removeAnchor() on the data provider. worldTracking.removeAnchor(forID: uuid) // Yes, I have also tried `removeAnchor(_ worldAnchor: WorldAnchor)` This works if there are more than one anchor in a scene. When I’m down to one remaining anchor, I can remove it. It seems to succeed (does not raise an error) but the next time I run the scene the removed anchor is back. This only happens when there is only one remaining anchor. do { // This always run, but it doesn't seem to "save" the removal when there is only one anchor left. try await worldTracking.removeAnchor(forID: uuid) } catch { // I have never seen this block fire! print("Failed to remove world anchor \(uuid) with error: \(error).") } I posted a video on my website if you want to see it happening. https://stepinto.vision/labs/lab-051-issues-with-world-tracking/ Here is the full code. Can you see if I’m doing something wrong? Is this a bug? struct Lab051: View { @State var session = ARKitSession() @State var worldTracking = WorldTrackingProvider() @State var worldAnchorEntities: [UUID: Entity] = [:] @State var placement = Entity() @State var subject : ModelEntity = { let subject = ModelEntity( mesh: .generateSphere(radius: 0.06), materials: [SimpleMaterial(color: .stepRed, isMetallic: false)]) subject.setPosition([0, 0, 0], relativeTo: nil) let collision = CollisionComponent(shapes: [.generateSphere(radius: 0.06)]) let input = InputTargetComponent() subject.components.set([collision, input]) return subject }() var body: some View { RealityView { content in guard let scene = try? await Entity(named: "WorldTracking", in: realityKitContentBundle) else { return } content.add(scene) if let placementEntity = scene.findEntity(named: "PlacementPreview") { placement = placementEntity } } update: { content in for (_, entity) in worldAnchorEntities { if !content.entities.contains(entity) { content.add(entity) } } } .modifier(DragGestureImproved()) .gesture(tapGesture) .task { try! await setupAndRunWorldTracking() } } var tapGesture: some Gesture { TapGesture() .targetedToAnyEntity() .onEnded { value in if value.entity.name == "PlacementPreview" { // If we tapped the placement preview cube, create an anchor Task { let anchor = WorldAnchor(originFromAnchorTransform: value.entity.transformMatrix(relativeTo: nil)) try await worldTracking.addAnchor(anchor) } } else { Task { // Get the UUID we stored on the entity let uuid = UUID(uuidString: value.entity.name) ?? UUID() do { try await worldTracking.removeAnchor(forID: uuid) } catch { print("Failed to remove world anchor \(uuid) with error: \(error).") } } } } } func setupAndRunWorldTracking() async throws { if WorldTrackingProvider.isSupported { do { try await session.run([worldTracking]) for await update in worldTracking.anchorUpdates { switch update.event { case .added: let subjectClone = subject.clone(recursive: true) subjectClone.isEnabled = true subjectClone.name = update.anchor.id.uuidString subjectClone.transform = Transform(matrix: update.anchor.originFromAnchorTransform) worldAnchorEntities[update.anchor.id] = subjectClone print("🟢 Anchor added \(update.anchor.id)") case .updated: guard let entity = worldAnchorEntities[update.anchor.id] else { print("No entity found to update for anchor \(update.anchor.id)") return } entity.transform = Transform(matrix: update.anchor.originFromAnchorTransform) print("🔵 Anchor updated \(update.anchor.id)") case .removed: worldAnchorEntities[update.anchor.id]?.removeFromParent() worldAnchorEntities.removeValue(forKey: update.anchor.id) print("🔴 Anchor removed \(update.anchor.id)") if let remainingAnchors = await worldTracking.allAnchors { print("Remaining Anchors: \(remainingAnchors.count)") } } } } catch { print("ARKit session error \(error)") } } } }
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219
May ’25
Keyboard Tracking
Hi! I'm currently experimenting on Apple Vision Pro with hand and head anchors. Is there a way to get an anchor linked to the apple magic keyboard (as the detection is already done to display inputs at the top)? Thanks in advance, Have a good day!
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650
Jul ’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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145
May ’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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357
Jul ’25
Missing Properties in BillboardComponent
In an earlier beta, BillboardComponent had rotationAxis and upDirection properties which allowed more fine-grained control of how an entity rotates towards the camera. Currently, it is only possible to orient the z axis of the entity. Looking at the robot in the documentation, the rotation of its z axis causes its feet to lift off the ground. Before, it was possible to restrain the rotation to one axis (y, for example) so that the robot's feet stayed on the ground with billboard.upDirection = [0, 1, 0] billboard.rotationAxis = [0, 1, 0] Is there an alternative way to achieve this? Are these properties (or similar) coming back?
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311
Mar ’25
Is `ParticleEmitterComponent` implemented for `RealityKit` on iOS?
Hi there, I was looking to add a particle emitter to my augmented reality app I'm developing using RealityKit. I'm targeting iOS. I noticed in the documentation for the ParticleEmitterComponent that it looks like iOS 18.0+ is supported, but when I try to use the ParticleEmitterComponent in my code in XCode, I get an error that it isn't found. Furthermore, this StackOverflow post seems to indicate that particle systems are not available for iOS. Would it be possible to get clarification on this?
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150
May ’25
Current Apple Forum about ARKit and visionOS
Recently, questions about ARKit/visionOS seem to be being asked in the Apple forum by internal Apple engineers. Inexperienced and untested makeshift features are being offered, putting average but experienced developers in a difficult position. They are unable to react and get something useful from the posts. Apple needs to review the situation.
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367
Sep ’25
Do you retain a reference to your content events in RealityView?
Do you retain a reference to your content (RealityViewContent) events? For example, the Manipulation Events docs from Apple use _ to discard the result. In theory the event should keep working while the content is alive. _ = content.subscribe(to: ManipulationEvents.WillBegin.self) { event in event.entity.components[ModelComponent.self]?.materials[0] = SimpleMaterial(color: .blue, isMetallic: false) } _ = content.subscribe(to: ManipulationEvents.WillEnd.self) { event in event.entity.components[ModelComponent.self]?.materials[0] = SimpleMaterial(color: .red, isMetallic: false) } We could store these events in state. I've seen this in a few samples and apps. @State var beginSubscription: EventSubscription? ... beginSubscription = content.subscribe(to: ManipulationEvents.WillBegin.self) { event in event.entity.components[ModelComponent.self]?.materials[0] = SimpleMaterial(color: .blue, isMetallic: false) } The main advantage I see is that we can be more explicit about when we remove the event. Are there other reasons to keep a reference to these events?
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591
Sep ’25
ARMeshAnchors are very unreliable on iPad Pro (4th gen)
Hello, We are developing an AR app that requires the lidar meshes. Unfortunately the ARMeshAnchors that allows us to retrieve the mesh data are very unreliable. It happens very often that the ARSession removes all ARMeshAnchors and takes anywhere from 5s to 30s to reappear. The planes detection (ARPlaneAnchors) are still working fine and the camera tracking is also working normally. I tried a basic ARKit sample app, and got the same behaviour as our own app. Is this a known issue ? Anything we can do to mitigate the issue ? Thank you
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313
Mar ’25