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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Blender to Reality Composer Pro 2.0 to SwiftUI + RealityKit visionOS Best Practices
Hi, I'm very new to 3D and am currently porting a SwiftUI iOS app to visionOS 2.0. I saw WWDC24 feature Blender in multiple spatial videos, and have begun integrating Blender models and animations into my VisionOS app (I would also like to integrate skeletons and programmatic rigging, more on that later). I'm wondering if there are “Best Practices” for this workflow - from Blender to USD to RCP 2.0 to visionOS 2 in Xcode. I’ve cobbled together the following that has some obvious holes: I’ve been able to find some pre-rigged and pre-animated models online that can serve as a great starting point. As a reference, here is a free model from SketchFab - a simple rigged skeleton with 6 built in animations: https://sketchfab.com/3d-models/skeleton-character-low-poly-8856e0138f424d68a8e0b40e185951f6 When exporting to USD from Blender, I haven’t been able to export more than one animation per USD file. Is there a workflow to export multiple animations in a single USDC file, or is this just not possible? As a temporary workaround, here is a python script I’ve been using to loop through all Blender animations, and export a model for each animation: import bpy import os # Set the directory where you want to save the USD files output_directory = “/path/to/export” # Ensure the directory exists if not os.path.exists(output_directory): os.makedirs(output_directory) # Function to export current scene as USD def export_scene_as_usd(output_path, start_frame, end_frame): bpy.context.scene.frame_start = start_frame bpy.context.scene.frame_end = end_frame # Export the scene as a USD file bpy.ops.wm.usd_export( filepath=output_path, export_animation=True ) # Save the current scene name original_scene = bpy.context.scene.name # Iterate through each action and export it as a USD file for action in bpy.data.actions: # Create a new scene for each action bpy.context.window.scene = bpy.data.scenes[original_scene].copy() new_scene = bpy.context.scene # Link the action to all relevant objects for obj in new_scene.objects: if obj.animation_data is not None: obj.animation_data.action = action # Determine the frame range for the action start_frame, end_frame = action.frame_range # Export the scene as a USD file output_path = os.path.join(output_directory, f"{action.name}.usdc") export_scene_as_usd(output_path, int(start_frame), int(end_frame)) # Delete the temporary scene to free memory bpy.data.scenes.remove(new_scene) print("Export completed.") I have also been able to successfully export rigging armatures as a single Skeleton - each “bone” showing getting imported into Reality Composer Pro 2.0 when exporting/importing manually. I would like to have all of these animations available in a single scene to be used in a RealityView in visionOS - so I have placed all animation models in a RCP scene and created named Timeline Action animations for each, showing the correct model and hiding the rest when triggering specific animations. I apply materials/textures to each so they appear the same, using Shader Graph. Then in SwiftUI I use notifications (as shown here - https://forums.developer.apple.com/forums/thread/756978) to trigger each RCP Timeline Action animation from code. Two questions: Is there a better way than to have multiple models of the same skeleton - each with a different animation - in a scene to be able to trigger multiple animations? Or would this require recreating Blender animations using skeleton rigging and keyframes from within RCP Timelines? If I want to programmatically create custom animations and move parts of the skeleton/armatures - do I need to do this by defining custom components in RCP, using IKRig and define movement of each of the “bones” in Xcode? I’m looking for any tips/tricks/workflow from experienced engineers or 3D artists that can create a more efficient/optimized workflow using Blender, USD, RCP 2 and visionOS 2 with SwiftUI. Thanks so much, I appreciate any help! I am very excited about all the new tools that keep evolving to make spatial apps really fun to build!
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1.2k
Apr ’25
Bones/joints data issue - USD file export from Blender to RCP
Hi, I'm developing a prototype VisionOS game. How to access the bones or joints information when exporting a USD file from Blender to RCP? The animation in RCP works fine and the joints' information is correctly embedded in the USDA file (with usdchecker). However, RCP does not read it in USDA, USDC or USDZ. It should be possible based on Apple WWDC24 (Compose Interactive 3D content in RCP). I want to attach and detach an entity to a particular bone in certain moments. So I need the bones' data. They are standard mixamo animations. My mesh is a single unified mesh. Using Blender 4.4
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716
Sep ’25
The AccessoryAnchor transform does not match any of the Accessory.LocationName options.
I am using AccessoryTrackingProvider from ARKit to get the transform of the PSVR2 controller via originFromAnchorTransform of the AccessoryAnchor. I also am trying to use AnchorEntity on the controller using RealityKit However, none of the three options for Accessory.LocationName, which should be used to define the AnchorEntity target, seem to match the position on the controller which is being sent from ARKit. The picture attached is showing two transforms: RealityKit - using .gripSurface to define the AnchoringComponent.Target.accesssory location. ARKit - using originFromAnchorTransform for AccessoryTrackingProvider. They are not aligned at the same point. As for the other options of Accessory.LocationName, using .aim is located at the tip of the controller and .grip is the same position as .gripSurface but with a different orientation. I am wondering why there is not an option for Accessory.LocationName that actually matches the transform captured by ARKit?
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Auto Rig Pro Mixamo Animation to RC Pro
Hi! I have been struggling with this for a little while and most of what I've found has not helped much. I hope to find more success here. Essentially, I have a model I've made in Blender. I rigged it using Auto Rig Pro, and I've also used ARP to add a Mixamo animation to it. That all works fine in Blender. However, when I try to import this model into RCP, I don't get the animation. The "default subtree animation" is completely empty. I attribute this to my lack of experience in this field but here's what I've attempted thus far: Pushing the Mixamo keyframes into an NLA strip. I'm pretty sure this is the correct line of action, but I'm definitely not doing something right. Baking the animation (?) I've made sure that I have animation checked when I export the model! Any ideas or reference projects would be lovely. I haven't really found much that has pushed me in the right direction. This project is, unfortunately, kind of time sensitive, so I would appreciate help ASAP. Thank you and let me know if I can add anymore context!
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413
4w
visionOS pushWindow being dismissed on app foreground
We seen to have found an issue when using the pushWindow action on visionOS. The issue occurs if the app is backgrounded then reopened by selecting the apps icon on the home screen. Any window that is opened via the pushWindow action is then dismissed. We've been able to replicate the issue in a small sample project. Replication steps Open app Open window via the push action Press the digital crown On the home screen select the apps icon again The pushed window will now be dismissed. There is a sample project linked here that shows off the issue, including a video of the bug in progress
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3w
RealityKit Entity ComponentSet does not conform to Sequence?
Hello, I'm trying to view the components of an Entity I'm creating in RealityKit by reading from a USDZ file. I have the following code snippet in my app. if let appleEntity = try? Entity.loadModel(named: "apple_tile") { let c = appleEntity.components for comp in c { // <- compiler error here print(comp) } } The compiler error I'm receiving says "For-in loop requires 'Entity.ComponentSet' to conform to 'Sequence'". However, I thought this was the case, according to the documentation for Entity.ComponentSet? Curious if anyone else has had this problem. Running XCode 15.4, and my Swift version is xcrun swift -version swift-driver version: 1.90.11.1 Apple Swift version 5.10 (swiftlang-5.10.0.13 clang-1500.3.9.4) Target: x86_64-apple-macosx14.0
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419
Mar ’25
VisionOS 26 - threadsPerThreadgroup limit causing crash on device (but not in simulator)
Hi all, I'm running into an issue with an app that previously worked fine on device using visionOS 2.0. After updating to visionOS 26, the same code runs fine in the simulator but crashes on the device with the following error: -[MTLDebugComputeCommandEncoder _validateThreadsPerThreadgroup:]:1330: failed assertion `(threadsPerThreadgroup.width(32) * threadsPerThreadgroup.height(32) * threadsPerThreadgroup.depth(1))(1024) must be <= 832. (kernel threadgroup size limit)` Is there any documented way to check or increase the allowed threadsPerThreadgroup size on Apple Vision Pro? Or any recommended workaround for this regression? Thanks in advance!
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183
Jun ’25
Merge MeshAnchor from Scene Reconstruction for Vision Pro
Hi there, I'm trying to merge the mesh anchor into a single mesh, but couldn't find any resources on this. Here is the code where I make the mesh from each mesh anchor, and assigned it to a model component with a shader graph material. func run(_ sceneRec: SceneReconstructionProvider) async { for await update in sceneRec.anchorUpdates { switch update.event { case .added, .updated: // Get or create entity for this anchor let anchorEntity = anchors[update.anchor.id] ?? { let entity = ModelEntity() root?.addChild(entity) anchors[update.anchor.id] = entity return entity }() // Remove any existing children for child in anchorEntity.children { child.removeFromParent() } // Generate the mesh from the anchor guard let mesh = try? await MeshResource(from: update.anchor) else { return } guard let shape = try? await ShapeResource.generateStaticMesh(from: update.anchor) else { continue } print("Mesh added, vertices: \(update.anchor.geometry.vertices.count), bounds: \(mesh.bounds)") // Get the material to use var material: RealityKit.Material if isMaterialLoaded, let loadedMaterial = self.shaderMaterial { material = loadedMaterial } else { // Use a temporary material until the shader loads var tempMaterial = UnlitMaterial() tempMaterial.color = .init(tint: .purple.withAlphaComponent(0.5)) material = tempMaterial } await MainActor.run { anchorEntity.components.set(ModelComponent(mesh: mesh, materials: [material])) anchorEntity.setTransformMatrix(update.anchor.originFromAnchorTransform, relativeTo: nil) // Add collision component with static flag - required for spatial interactions anchorEntity.components.set(CollisionComponent( shapes: [shape], isStatic: true, filter: .default )) // Make entity interactive - enables spatial taps, drags, etc. anchorEntity.components.set(InputTargetComponent()) let shadowComponent = GroundingShadowComponent( castsShadow: true, receivesShadow: true ) anchorEntity.components.set(shadowComponent) } I then use a spatial tap gesture to set the position parameter in the shader graph material that creates a nice gradient from the tap position on the mesh to the rest of the mesh. SpatialTapGesture() .targetedToAnyEntity() .onEnded { value in let tappedEntity = value.entity // Check if the tapped entity is a child of tracking.meshAnchors if isChildOfMeshAnchors(entity: tappedEntity) { // Get local position (in the entity's coordinate space) let localPosition = value.location3D // Convert to world position (scene coordinate space) let worldPosition = value.convert(localPosition, from: .local, to: .scene) print("Tapped mesh anchor at local position: \(localPosition)") print("Tapped mesh anchor at world position: \(worldPosition)") // Update the material parameter with the tap position updateMaterialTapPosition(entity: tappedEntity, position: worldPosition) } else { print("Tapped entity is not a mesh anchor") } } } My issue is that because there are several mesh anchors, the gradient often gets cut off by the edge of the mesh generated from the mesh anchor as suppose to a nice continuous gradient across the entire scene reconstructed mesh I couldn't find any documentations on how to merge mesh from mesh anchors, any tips would be helpful! Thank you!
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Mar ’25
Scene not found after changes in Reality Composer Pro
randomly, the app does not work after small changes in Reality Composer. Small changes like scaling a object a tiny bit. to fix the error, i have to change another element in reality composer and hope for the best. if this does not help, i change (transform) something else, or deactive/activate something to get the project working again. I can't see a pattern why the Reality Composer Project sometimes gets in a state where it does not compile anymore.
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1.9k
3w
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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434
Feb ’25
Is ARGeoTrackingConfiguration always more accurate than ARWorldTrackingConfiguration for world scale AR?
We are working on a world scale AR app that leverages the device location and heading to place objects in the streets, so that they are correctly and stably anchored to certain locations. Since the geo-tracking imagery is only available in certain cities and areas, we are trying to figure out how to fallback when geo-tracking is not available as the device move away, to still retain good AR camera accuracy. We might need to come up with some algorithm using the device GPS, to line up the ARCamera with our objects. Question: Does geo-tracking always provide greater than or equal to the accuracy of world tracking, for a GPS outdoor AR experience? If so, we can simply use the ARGeoTrackingConfiguration for the entire time, and rely on the ARView keeping itself aligned. Otherwise, we need to switch between it and ARWorldTrackingConfiguration when geo-tracking is not available and/or its accuracy is low, then roll our own algorithm to keep the camera aligned. Thanks.
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1.1k
Oct ’25
ReplayKit start and stop capture breaks and give me an error when switching from Immersive to Mixed and back.
Hi, I'm developing a virtual camera system using ReplayKit to capture scene video by directly accessing raw video buffers. The capture mechanism works flawlessly when repeatedly starting and stopping video capture within a continuous immersive environment. However, a critical issue arises when interrupting the immersive space: Step 1: Enter immersive environment and start and stop capture videos(Multiple times with no issues) Step 2: Press the crown button to exit the immersive environment Step 3: Return to the immersive space subsequently Step 4: Attempt to start the video capture At this point, the startCapture method throws an unexpected error, disrupting the video capture workflow. This is the Xcode error that I see " [ERROR] -[RPScreenRecorder startCaptureWithHandler:completionHandler:]_block_invoke_2:500 failed to start due to error: Error Domain=com.apple.ReplayKit.RPRecordingErrorDomain Code=-5803 "Recording failed to start" UserInfo={NSLocalizedDescription=Recording failed to start}" I have tried all possible ways to stopCapture including OnDisappear and other methods and nothing seems to solve this.
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324
Mar ’25
VisionOS Enterprise API Not Working
My development team admin requested the Enterprise API for camera access on the vision pro. We got that granted, got a license for usage, and got instructions for integrating it with next steps. We did the following: Even when I try to download and run the sample project for "Accessing the Main Camera", and follow all the exact instructions mentioned here: https://developer.apple.com/documentation/visionos/accessing-the-main-camera I am just unable to receive camera frames. I added the capabilities, created a new provisioning profile with this access, added the entitlements to info.plist and entitlements, replaced the dummy license file with the one we were sent, and also have a matching bundle identifier and development certificate, but it is still not showing camera access for some reason. "Main Camera Access" shows up in our Signing & Capabilities tab, and we also added the NSMainCameraDescription in the Info.plist and allow access while opening the app. None of this works. Not on my app, and not on the sample app that I just downloaded and tried to run on the Vision Pro after replacing the dummy license file.
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812
Dec ’25
Degraded RoomPlan performance
We have been using RoomPlan in our app for 2+ years. Through a combination of in-app and manual coaching on scanning best practices, most users are able to achieve high-quality scans on a consistent basis. In recent weeks, however, we have observed an increase in reports of degraded scanning performance, even from veteran users who had not previously encountered issues. The RoomCaptureView overlay is jittery and crooked, and the resulting scan file has significant issues, even for simple, well-lit rectangular rooms. It is difficult to troubleshoot these issues given the number of variables at play, and the overall volume of reports is still relatively low, but we'd appreciate any guidance on known issues or workarounds that could help unblock our users who are being affected by this. I noticed that this post includes an acknowledgement of FB14454922 and FB15035788. Our issues seem slightly different as the scans are simply inaccurate and jittery without failing outright. I haven't found any other threads on similar issues.
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2.1k
3w
ManipulationComponent create parent/child crash
Hello, If you add a ManipulationComponent to a RealityKit entity and then continue to add instructions, sooner or later you will encounter a crash with the following error message: Attempting to move entity “%s” (%p) under “%s” (%p), but the new parent entity is currently being removed. Changing the parent/child entities of an entity in an event handler while that entity is already being reassigned is not supported. CoreSimulator 1048 – Device: Apple Vision Pro 4K (B87DD32A-E862-4791-8B71-92E50CE6EC06) – Runtime: visionOS 26.0 (23M336) – Device Type: Apple Vision Pro The problem occurs precisely with this code: ManipulationComponent.configureEntity(object) I adapted Apple's ObjectPlacementExample and made the changes available via GitHub. The desired behavior is that I add entities to ManipulationComponent and then Realitiykit runs stably and does not crash randomly. GitHub Repo Thanks Andre
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495
Oct ’25