I have developed a fun living diorama world using Reality Composer Pro and XCode. Everything is as it should be, and it looks/works great ... until it does not. If I seem to make any change to any of the 10 timelines that I am using (all on the same scene, no nested scenes), running the app in simulator, device, and via testflight throws errors around compiled timelines, leading to the black screen of death. Every time I clean and run, the timelines in questions might change. Its very frustrating and impossible to track down. Heres are some examples. AssetLoadRequest failed because asset failed to load '/ (3661553931319769725 Timeline (RealityFileAsset)URL/file:///var/containers/Bundle/Application/F4408256-6014-4264-9E4B-F74AEF0EDE53/SantasVillage.app/RealityKitContent_RealityKitContent.bundle/RealityKitContent.reality/Timeline_779.compiledtimeline)' (failed to register asset) Asset / (13631856135570808851 AnimationLibraryAsset (RealityFileAsset)URL/file:///var/containers/Bundle/Application/F4408256-6014-4264-9E4B-F74AEF0EDE53/SantasVillage.app/RealityKitContent_RealityKitContent.bundle/RealityKitContent.reality/AnimationLibraryAsset_1.compiledanimationlibraryasset) failure: failed to register asset Asset 10430065658338454790 AnimationScene (RealityFileAsset)URL/file:///var/containers/Bundle/Application/F4408256-6014-4264-9E4B-F74AEF0EDE53/SantasVillage.app/RealityKitContent_RealityKitContent.bundle/RealityKitContent.reality/AnimationScene_14.compiledanimationscene failure: failed to register asset I went with recommended fixes of closing RCP > Clean Build Folder > Delete Derrived Date (multiple ways) > Re-Open Xcode > Reset Package Cache > Re-Open RCP via XCode > Make a Change > Save > Clean Build Folder Again > Run. Sometimes it works. Most times it does not. I then found my own little work-around, but its not always working as is literally costing me days of wasted time messing around with this. I will DISABLE all timelines, do the above clean method, rerun with no timelines, and it resolves. Then, turn on timelines ONE BY ONE and run until I get another error. Then, rebuild that timeline and nothing else. This is not sustainable. There must be some better way to do this? Or, perhaps I am doing something wrong? Please help if you can.

I have an arguably massive project and am not sure if the issue is with the assets or my approach in the code. the error says : Tool terminated due to error "SIGNAL 6:Abort trap:6" Basically I have around 15-20 assets (usda files built out of usdz files). In the code i am loading a scene with all the usda files and then have the functions to enable and disable a particular asset when needed. This was working as intended when i am using dummy assets(with less polygons, lesser textures) But when i placed the actual assets the error appears and persists. Do I have a bad approach of loading all the scenes at once? Previously i have used an approach which loads the scenes when needed and that involved some lag before rendering the assets. But my current approach(when using dummies) works like a dime rendering and hiding the assets in realtime with no lag. Kindly suggest any workarounds.

A ShaderGraphMaterial with an Occlusion Surface Output generated with RealityComposer 2 fails to load on iOS 18 and macOS 15 with the following error: RealityFoundation.ShaderGraphMaterial.LoadError.invalidTypeFound (https://developer.apple.com/documentation/realitykit/shadergraphmaterial/loaderror/invalidtypefound) This happens with both https://developer.apple.com/documentation/shadergraph/realitykit/occlusion-surface-(realitykit) and https://developer.apple.com/documentation/shadergraph/realitykit/shadow-receiving-occlusion-surface-(realitykit) RealityView { content in do { let bgEntity = ModelEntity(mesh: .generateCone(height: 0.5, radius: 0.1), materials: [SimpleMaterial(color: .red, isMetallic: true)]) bgEntity.position.z = -0.2 content.add(bgEntity) let occlusionMaterial = try await ShaderGraphMaterial(named: "/Root/OcclusionMaterial", from: "OcclusionMaterial") let testEntity = ModelEntity(mesh: .generateSphere(radius: 0.4), materials: [occlusionMaterial]) content.add(testEntity) content.cameraTarget = testEntity } catch { print("Shader Graph Load Error:") dump(error) } } .realityViewCameraControls(.orbit) .edgesIgnoringSafeArea(.all) Feedback ID: FB15081296

Apple's new Spatial Personas use Gaussian Splatting, but I have not found any APIs for visionOS to display a Gaussian Splat like a PLY file. Am I just missing the Apple documentation? If not, are there common practices developers are using for displaying Gaussian Splats in visionOS?

I’m trying to use EXR lightmaps to overlay baked lighting on top of a base texture in the RCP Shader Graph. When I multiply an EXR image set to Image(float) with an 8-bit base texture, the output becomes Image(float). I can’t connect that to the BaseColor input on the UnlitSurface node, since it only accepts Color3f. I expected to be able to use a Convert node between the Multiply node and the BaseColor input, but when I do that, the result becomes black and white instead of the expected outcome: the EXR multiplied with the base texture using a baseline value of 1, where values below 1 in the EXR would darken the base texture and values above 1 would brighten it. Is there any documentation on how to properly overlay a 32-bit EXR lightmap in the RCP Shader Graph, or is the black-and-white output from the Convert node a bug?

I’m currently developing a visionOS app that includes an RCP scene with a large USDZ file (around 2GB). Each time I make adjustments to the CG model in Blender, I export it as USDZ again, place it in the RCP scene, and then build the app using Xcode. However, because the USDZ file is quite large, the build process takes a long time, significantly slowing down my development speed. For example, I’d like to know if there are any effective ways to: Improve overall build performance Reduce the time between updating the USDZ file and completing the build Any advice or best practices for optimizing this workflow would be greatly appreciated. Best regards, Sadao

I have a question about Apple’s preinstalled visionOS app “Encounter Dinosaurs.” In this app, the dinosaurs are displayed over the real-world background, but the PhysicallyBasedMaterial (PBM) in RealityKit doesn’t appear to respond to the actual brightness of the environment. Even when I change the lighting in the room, the dinosaurs’ brightness and shading remain almost the same. If this behavior is intentional — for example, if the app disables real-world lighting influence or uses a fixed lighting setup — could someone explain how and why it’s implemented that way?

Most models are only available as glb or fbx, so I usually reexport them into usdz using Blender. When I import them into Reality Composer Pro, Mesh, Textures etc look great, but in the Animation Library subsection all I can see is one default subtree animation. In Blender I can see all available animations and play them individually. The default subtree animation just plays the default idle animation. In fact when I open the nonlinear animation view in Blender and select a different animation as the default animation, the exported usdz shows the newly selected animation as default subtree animation. I can see in the Apple sample apps models can have multiple animations in their Animation Library. I'm using the latest Blender 4.5 and the usdz exporter should be working properly?

In Reality Composer Pro, why is the Sky Sphere so much larger than the Sky Dome? By my estimate, the Sky Sphere has a radius of 100m, while the Sky only has a radius of only 12m.

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.

I have a question I guess more for the Apple team. But why are there no totally 3D experiences for the Vision Pro lineup? I know they have given us tools to implement unity 3D games into iPhone and I guess you can also build it in RealityKit. But why at this moment are 3D games limited to just iPad and iPhone and can't you bring that into Vision Pro? Just to explain. When I say a totally 3D game, I mean games like Gorn. I mean the Vision Pro is definitely powerful enough, but it just feels limited to tabletop games and AR games. Is this something Apple is thinking about implementing?

Developing a prototype Vision Pro app and would like to render a 3D scene made from Reality Composer Pro on an image anchor in a RealityView. But I have no luck so far to make it work and need some guidance to move on. I got the image file stored in the assets like below: And from below is the source codes: import SwiftUI import RealityKit import RealityKitContent struct AnchorView: View { @State var imageEntity: Entity = { let anchorEntity = AnchorEntity(.image(group: "AR Resources", name: "reanchor")) return anchorEntity }() var body: some View { RealityView { content in do { // Add the initial RealityKit content if let scene = try? await Entity(named: "Scene", in: realityKitContentBundle) { imageEntity.addChild(scene) content.add(imageEntity) } } catch { print("Error occurs when adding reality view content: \(error)") } } } }

I'm having a heck of a time getting this to work. I'm trying to add an event notification at the end of a timeline animation to trigger something in code but I'm not receiving the notification from RC Pro. I've watched that Compose Interactive 3D Content video quite a few times now and have tried many different ways. RC Pro has the correct ID names on the notifications. I'm not a programmer at all. Just a lowly 3D artist. Here is my code... import SwiftUI import RealityKit import RealityKitContent extension Notification.Name { static let button1Pressed = Notification.Name("button1pressed") static let button2Pressed = Notification.Name("button2pressed") static let button3Pressed = Notification.Name("button3pressed") } struct MainButtons: View { @State private var transitionToNextSceneForButton1 = false @State private var transitionToNextSceneForButton2 = false @State private var transitionToNextSceneForButton3 = false @Environment(AppModel.self) var appModel @Environment(\.dismissWindow) var dismissWindow // Notification publishers for each button private let button1PressedReceived = NotificationCenter.default.publisher(for: .button1Pressed) private let button2PressedReceived = NotificationCenter.default.publisher(for: .button2Pressed) private let button3PressedReceived = NotificationCenter.default.publisher(for: .button3Pressed) var body: some View { ZStack { RealityView { content in // Load your RC Pro scene that contains the 3D buttons. if let immersiveContentEntity = try? await Entity(named: "MainButtons", in: realityKitContentBundle) { content.add(immersiveContentEntity) } } // Optionally attach a gesture if you want to debug a generic tap: .gesture( TapGesture().targetedToAnyEntity().onEnded { value in print("3D Object tapped") _ = value.entity.applyTapForBehaviors() // Do not post a test notification here—rely on RC Pro timeline events. } ) } .onAppear { dismissWindow(id: "main") // Remove any test notification posting code. } // Listen for distinct button notifications. .onReceive(button1PressedReceived) { (output) in print("Button 1 pressed notification received") transitionToNextSceneForButton1 = true } .onReceive(button2PressedReceived.receive(on: DispatchQueue.main)) { _ in print("Button 2 pressed notification received") transitionToNextSceneForButton2 = true } .onReceive(button3PressedReceived.receive(on: DispatchQueue.main)) { _ in print("Button 3 pressed notification received") transitionToNextSceneForButton3 = true } // Present next scenes for each button as needed. For example, for button 1: .fullScreenCover(isPresented: $transitionToNextSceneForButton1) { FacilityTour() .environment(appModel) } // You can add additional fullScreenCover modifiers for button 2 and 3 transitions. } }

I'm placing sphere at finger tip and updating its position as hand move. Finger joint tracking functions correctly, but I’ve observed noticeable latency in hand tracking updates whenever a UITextView becomes active. This lag happens intermittently during app usage, lasting about 5–10 seconds, after which the latency disappears and the sphere starts following the finger joints immediately. When I open the immersive space for the first time, the profiler shows a large performance spike upto 328%. After that, it stabilizes and runs smoothly. Note: I don’t observe any lag when CPU usage spikes to 300% (upon immersive view load) yet the lag still occurs even when CPU usage remains below 100%. I’m using the following code for hand tracking: private func processHandTrackingUpdates() async { for await update in handTracking.anchorUpdates { let handAnchor = update.anchor if handAnchor.isTracked { switch handAnchor.chirality { case .left: leftHandAnchor = handAnchor updateHandJoints(for: handAnchor, with: leftHandJointEntities) case .right: rightHandAnchor = handAnchor updateHandJoints(for: handAnchor, with: rightHandJointEntities) } } else { switch handAnchor.chirality { case .left: leftHandAnchor = nil hideAllJoints(in: leftHandJointEntities) case .right: rightHandAnchor = nil hideAllJoints(in: rightHandJointEntities) } } await MainActor.run { handTrackingData.processNewHandAnchors( leftHand: self.leftHandAnchor, rightHand: self.rightHandAnchor ) } } } And here’s the function I’m using to update the joint positions: private func updateHandJoints( for handAnchor: HandAnchor, with jointEntities: [HandSkeleton.JointName: Entity] ) { guard handAnchor.isTracked else { hideAllJoints(in: jointEntities) return } // Check if the little finger tip and intermediate base are both tracked. if let tipJoint = handAnchor.handSkeleton?.joint(.littleFingerTip), let intermediateBaseJoint = handAnchor.handSkeleton?.joint(.littleFingerIntermediateTip), tipJoint.isTracked, intermediateBaseJoint.isTracked, let pinkySphere = jointEntities[.littleFingerTip] { // Convert joint transforms to world space. let tipTransform = handAnchor.originFromAnchorTransform * tipJoint.anchorFromJointTransform let intermediateBaseTransform = handAnchor.originFromAnchorTransform * intermediateBaseJoint.anchorFromJointTransform // Extract positions from the transforms. let tipPosition = SIMD3<Float>(tipTransform.columns.3.x, tipTransform.columns.3.y, tipTransform.columns.3.z) let intermediateBasePosition = SIMD3<Float>(intermediateBaseTransform.columns.3.x, intermediateBaseTransform.columns.3.y, intermediateBaseTransform.columns.3.z) // Calculate the midpoint. let midpointPosition = (tipPosition + intermediateBasePosition) / 2.0 // Position the sphere at the midpoint and make it visible. pinkySphere.isEnabled = true pinkySphere.transform.translation = midpointPosition } else { // If either joint is not tracked, hide the sphere. jointEntities[.littleFingerTip]?.isEnabled = false } // Update the positions of all other hand joint spheres. for (jointName, entity) in jointEntities { if jointName == .littleFingerTip { // Already handled the pinky above. continue } guard let joint = handAnchor.handSkeleton?.joint(jointName), joint.isTracked else { entity.isEnabled = false continue } entity.isEnabled = true let jointTransform = handAnchor.originFromAnchorTransform * joint.anchorFromJointTransform entity.transform.translation = SIMD3<Float>(jointTransform.columns.3.x, jointTransform.columns.3.y, jointTransform.columns.3.z) } } I’ve attached both a profiler trace and a video recording from Vision Pro that clearly demonstrate the issue. Profiler: https://drive.google.com/file/d/1fDWyGj_fgxud2ngkGH_IVmuH_kO-z0XZ Vision Pro Recordings: https://drive.google.com/file/d/17qo3U9ivwYBsbaSm26fjaOokkJApbkz- https://drive.google.com/file/d/1LxTxgudMvWDhOqKVuhc3QaHfY_1x8iA0 Has anyone else experienced this behavior? My thought is that there might be some background calculations happening at the OS level causing this latency. Any guidance would be greatly appreciated. Thanks!

I am creating a vision pro app with a 3D model, it has a mesh hierarchy of head, hands, feet etc. I want the character to look towards the camera, but am not able to access head of character through sceneKit nor reality kit. when I try to print names of the child meshes, it only prints till the character, it does iterate through all the body parts. Can anyone help?

Hi everyone, I’m currently learning about ParticleEmitterComponentParticleEmitterComponent and exploring the sample app provided in the Simulating particles in your visionOS app documentation. In the sample app, when I set the EmitterPreset to fireworks from the settings panel on the left side of the window and choose SystemImage, I noticed two issues: The image applied to mainEmitter appears clipped or cropped. The image on spawnedEmitter does not update to the selected SystemImage. What I want to achieve: Apply the same SystemImage to both mainEmittermainEmitter and spawnedEmitterspawnedEmitter so that it displays correctly without clipping. Remove the animation that changes the size of spawnedEmitterspawnedEmitter over time and keep it at a constant size. Could someone explain which properties should be adjusted to achieve this behavior? Any guidance or examples would be greatly appreciated. Thanks in advance!

I have a scene that has been assembled in RCP but I'm losing the correct hierarchy and transforms when running the scene in the headset or the simulator. This is in RCP: This is at runtime with the debugger: As you can see the "MAIN_WAGON" entity is gone and part of the hierarchy are now children of "TRAIN_ROOT" instead. Another issue is that not only part of the hieararchy disappears, it also reverts back to default values of the transform instead of what is set in RCP: This is in RCP: This is in the simulator/headset: I'm filing a feedback ticket too and will post the number here. Anyone had a similar issue and found a fix or workaround ?

Hello everyone, I am currently developing an experience for visionOS using RealityKit and I would like to achieve volumetric light effects, such as visible light rays or shafts through fog or dust. I found this GitHub project: https://github.com/robcupisz/LightShafts, which demonstrates the kind of visual style I am aiming for. I would like to know if there is a way to create similar effects using RealityKit on visionOS. So far, I have experimented with DirectionalLight, SpotLight, ImageBasedLight, and custom materials (e.g., additive blending on translucent meshes), but none of these approaches can replicate the volumetric light shaft look shown in the repository above. Questions: Is there a recommended technique or workaround in RealityKit to simulate light shafts or volumetric lighting? Is creating a custom mesh (e.g., cone or volume geometry with gradient alpha and additive blending) the only feasible method? Are there any examples, best practices, or sample projects from Apple or other developers that showcase a similar visual style? Any advice or hints would be greatly appreciated. Thank you in advance!

Hi there, I'm developing a visionOS app that is using the anchor points and mesh from SceneReconstructionProvider anchor updates. I load an ImmersiveSpace using a RealityView and apply a ShaderGraphMaterial (from a Shader Graph in Reality Composer Pro) to the mesh and use calls to setParameter to dynamically update the material on very rapid frequency. The mesh is locked (no more updates) before the calls to setParameter. This process works for a few minutes but then eventually I get the following error in the console: assertion failure: Index out of range (operator[]:line 789) index = 13662, max = 1 With the following stack trace: Thread 1 Queue : com.apple.main-thread (serial) #0 0x00000002880f90d0 in __abort_with_payload () #1 0x000000028812a6dc in abort_with_payload_wrapper_internal () #2 0x000000028812a710 in abort_with_payload () #3 0x0000000288003f40 in _os_crash_msg () #4 0x00000001dc9ff624 in re::ecs2::ComponentBucketsBase::addComponent () #5 0x00000001dc9ffadc in re::ecs2::ComponentBucketsBase::moveComponent () #6 0x00000001dc8b0278 in re::ecs2::MaterialParameterBlockArrayComponentStateImpl::processPreparingComponents () #7 0x00000001dc8b05e4 in re::ecs2::MaterialParameterBlockArraySystem::update () #8 0x00000001dd008744 in re::Scheduler::executePhase () #9 0x00000001dc032ec4 in re::Engine::executePhase () #10 0x0000000248121898 in RCPSharedSimulationExecuteUpdate () #11 0x00000002264e488c in __59-[MRUISharedSimulation _doJoinWithConnectionContext:error:]_block_invoke.44 () #12 0x0000000268c5fe9c in _UIUpdateSequenceRunNext () #13 0x00000002696ea540 in schedulerStepScheduledMainSectionContinue () #14 0x000000026af8d284 in UC::DriverCore::continueProcessing () #15 0x00000001a1bd4e6c in CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION () #16 0x00000001a1bd4db0 in __CFRunLoopDoSource0 () #17 0x00000001a1bd44f0 in __CFRunLoopDoSources0 () #18 0x00000001a1bd3640 in __CFRunLoopRun () #19 0x00000001a1bce284 in _CFRunLoopRunSpecificWithOptions () #20 0x00000001eff12d2c in GSEventRunModal () #21 0x00000002697de878 in -[UIApplication _run] () #22 0x00000002697e33c0 in UIApplicationMain () #23 0x00000001b56651e4 in closure #1 (Swift.UnsafeMutablePointer<Swift.Optional<Swift.UnsafeMutablePointer<Swift.Int8>>>) -> Swift.Never in SwiftUI.KitRendererCommon(Swift.AnyObject.Type) -> Swift.Never () #24 0x00000001b5664f08 in SwiftUI.runApp<τ_0_0 where τ_0_0: SwiftUI.App>(τ_0_0) -> Swift.Never () #25 0x00000001b53ad570 in static SwiftUI.App.main() -> () () #26 0x0000000101bc7b9c in static MetalRendererApp.$main() () #27 0x0000000101bc7bdc in main () #28 0x0000000197fd0284 in start () Any advice on how to solve this or prevent the error? Thanks!

Hello, I'm working with the new PortalComponent introduced in visionOS 2.0, and I've encountered some issues when transitioning entities between virtual and real-world spaces using crossingMode. Specifically: Lighting inconsistency: When CG content (ModelEntities with PhysicallyBasedMaterial) crosses the portal from virtual space into the real environment, the way light reflects on the objects changes noticeably. This causes a jarring visual effect, as the same material appears differently depending on the space it's in. Unnatural transition visuals: During the transition, the CG models often appear to "emerge from the wall," especially when crossing from virtual to real. This ruins the immersive illusion and feels visually unnatural. IBL adjustment attempts: I’ve tried adding an ImageBasedLightComponent to the world entity, and while it slightly improves the lighting consistency, the issue still remains to a noticeable degree. My goal is to create a seamless visual experience when CG entities cross between spaces, without sudden lighting shifts or immersion-breaking geometry reveals. Has anyone else experienced similar issues? Is there a recommended setup or workaround to better control lighting and visual fidelity when using crossingMode with portals in visionOS 2.0? Any guidance would be greatly appreciated. Thank you!