RealityKit

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Simulate and render 3D content for use in your augmented reality apps using RealityKit.

RealityKit Documentation

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You cannot debug in simulator
I can't create any breakpoint in my Xcode after I upgraded to macOS 15.4 macOS: Version 15.4 (24E248) visionOS Simulator: 2.3 Xcode: Version 16.2 (16C5032a) My app works well without any breakpoints. But if I create any breakpoint it shows me this: Couldn't find the Objective-C runtime library in loaded images. Message from debugger: The LLDB RPC server has crashed. You may need to manually terminate your process. The crash log is located in ~/Library/Logs/DiagnosticReports and has a prefix 'lldb-rpc-server'. Please file a bug and attach the most recent crash log.
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Apr ’25
Feature Request: Support .reality File Export in Reality Composer Pro for Mac
I am an AR developer working on Apple Silicon Macs. Currently, Reality Composer Pro does not allow exporting .reality files, and Reality Composer (classic) is not available for Apple Silicon. This creates a gap in the workflow for ARKit/RealityKit developers who need interactive .reality files for use in Xcode projects. Having the ability to export .reality files directly from Reality Composer Pro on Mac would greatly streamline development and enable a fully native workflow on modern Macs. Alternatively, bringing Reality Composer (classic) to Apple Silicon would also resolve this issue. I have submitted this as a feature request via Feedback Assistant (FB17900386). I encourage others with similar needs to reply or submit feedback as well. Thank you!
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Jul ’25
RealityView content scale factor
Hi, following the recent deprecation of SceneKit, I'm trying to move a couple of my SceneKit projects to RealityKit. One thing I can't seem to find is how to change the content scale factor when using a RealityView in SwiftUI. It was really easy to do in SceneKit with just a SCNView property, and it seems that it's also possible when using ARView, but I can't find a way to do it with a RealityView. Maybe it's a SwiftUI limitation?
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Jul ’25
visionOS + Unity PolySpatial: Is 15,970 MeshFilters the True Upper Limit for Industrial Scenes?
Breaking Through PolySpatial's ~8k Object Limit – Seeking Alternative Approaches for Large-Scale Digital Twins Confirmed: PolySpatial make Doubles MeshFilter Count – Hard Limit at ~8k Active Objects (15.9k Total) Project Context & Research Goals I’m developing an industrial digital twin application for Apple Vision Pro using Unity’s PolySpatial framework (RealityKit rendering in Unbounded_Volume mode). The scene contains complex factory environments with: Production line equipment Many fragmented grid objects need to be merged.) Dynamic product racks (state-switchable assets) Animated worker avatars To optimize performance, I’m systematically testing visionOS’s rendering capacity limits. Through controlled stress tests, I’ve identified a critical threshold: Key Finding When the total MeshFilter count reaches 15,970 (system baseline + 7,985 user-created objects × 2 due to PolySpatial cloning), the application crashes consistently. This suggests: PolySpatial’s mirroring mechanism effectively doubles GameObject overhead An apparent hard limit exists around ~8k active mesh objects in practice Objectives for This Discussion Verify if others have encountered similar limits with PolySpatial/RealityKit Understand whether this is a: Memory constraint (per-app allocation) Render pipeline limit (Metal draw calls) Unity-specific PolySpatial behavior Explore optimization strategies beyond brute-force object reduction Why This Matters Industrial metaverse applications require rendering thousands of interactive objects . Confirming these limits will help our team: Design safer content guidelines Prioritize GPU instancing/LOD investments Potentially contribute back to PolySpatial’s optimization I’d appreciate insights from engineers who’ve: Pushed similar large-scale scenes in visionOS Worked around PolySpatial’s cloning overhead Discovered alternative capacity limits (vertices/draw calls)
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Oct ’25
Subject: Handling Z-Up Blender USDZ Models in RealityKit (visionOS) for Transform Updates
Hello everyone, I'm working on a visionOS application using RealityKit and am encountering a common coordinate system challenge when integrating 3D models created in Blender. My goal is to display and dynamically update the Transform (position, rotation, scale) of models created in Blender within RealityKit. The issue arises because Blender's default coordinate system is Z-up, and while exporting to USD/USDZ, I don't have a reliable "Y-up" export option that correctly reorients the model and its transform data for RealityKit's Y-up convention. This means I'm essentially exporting models with their "up" direction along the Z-axis. When I load these Z-up exported models into RealityKit, they are often oriented incorrectly. To then programmatically update their Transform (e.g., move them, rotate them based on game logic, or apply physics), I need to ensure that the Transform values I set align with RealityKit's Y-up system, even though the original model data was authored in a Z-up context. My questions are: What is the recommended transformation process (e.g., using simd_quatf or simd_float4x4) to convert a Transform that was conceptually defined in a Z-up coordinate system to RealityKit's Y-up coordinate system? Specifically, when I have a Transform (or its translation, rotation, scale components) from a Z-up context, how should I apply this to a RealityKit Entity so it appears and behaves correctly in a Y-up world? Are there any existing convenience APIs or helper functions within RealityKit, simd, or other Apple frameworks that simplify this Z-up to Y-up Transform conversion process? Or is a manual application of a transformation quaternion (e.g., simd_quatf(angle: -.pi / 2, axis: [1, 0, 0])) the standard approach? Any guidance, code examples, or best practices from those who have faced similar challenges would be greatly appreciated! Thank you.
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Jul ’25
RealityKit and USDZ: Winding Order Issue with Negatively Scaled Meshes
Hi all, I've encountered a potential issue with how the winding order of geometry is handled when their transformations involve negative scaling. I created a simple test asset, a single triangle, to demonstrate this. The triangle's vertices are defined in a counter-clockwise ("right-handed") winding order, and its transform has a negative scale on the X-axis. According to the OpenUSD specification, this negative determinant in the transformation matrix should effectively reverse the winding order of the geometry: However, any given gprim's local-to-world transformation can flip its effective orientation, when it contains an odd number of negative scales. This condition can be reliably detected using the (Jacobian) determinant of the local-to-world transform: if the determinant is less than zero, then the gprim's orientation has been flipped, and therefore one must apply the opposite handedness rule when computing its surface normals (or just flip the computed normals) for the purposes of hidden surface detection and lighting calculations. When I view the asset in tools like Blender or Preview on macOS, it behaves as expected. The triangle's effective orientation is flipped to CW. However, when the same asset is viewed in Reality Composer Pro or with QuickLook on iOS, its effective orientation remains CCW. In other words, the triangle faces the opposite direction. My questions for the community and Apple are: Is this behavior in RealityKit a known issue? If this is a known issue, is there official guidance for DCC tools on how to export USDZ assets to ensure they appear correctly in the Apple ecosystem? Any insights or recommendations would be greatly appreciated.
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Nov ’25
Moving from SceneKit - fog missing
I am rewriting an unfinished SceneKit project as RealityKit (NonAR). As far as I can see, RealityKit is missing basic fog functionality? Fog was simple & easy to implement in SCeneKit (fogStartDistance / fogEndDistance / fogDensityExponent / fogColor). Are there any plans to implement something like this in RealityKit? Are there any simple workarounds?
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Aug ’25
Multiply exr lightmap in Reality Composer Pro Shader Graph
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?
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Skybox for iOS/swiftUI not working
I have tried every combination of suggestions to get a skybox to appear. Using swiftUI, realityKit and iOS. Non immersive environment. Does anyone have code that works to display a skybox. When i use a do/catch loop i get environmentResource not found. I have checked the syntax, ensured the folder is referencing the target, used the same name for the folder as the file, the file is a .hdr (i assume this is supported), i have moved the file folder to the top level - no change.
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Dec ’25
Anchor an Reality scene on an image anchor
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)") } } } }
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1.2k
Sep ’25
Reality Composer Pro 2.0 shader graphs can't be loaded on visionOS 1
Using Reality Composer Pro 2.0, I created a simple shader graph that displays a texture on an unlit surface: On visionOS 2 beta, I can successfully use ShaderGraphMaterial(named:from:in:) to load that shader graph material and assign it to a model entity. However, on visionOS 1.2 and earlier, either in Simulator or on the device, ShaderGraphMaterial(named:from:in:) fails and I see the following logged to the console: If, using Reality Composer Pro 1.0, I experimentally open the same project and delete and recreate exactly the same nodes above, then ShaderGraphMaterial(named:from:in:) works as expected on visionOS 1.2. Is it a known issue that Reality Composer 2 can't be used with visionOS 1? Is this intentional behavior? I've submitted feedback as FB14828873, including a sample project and repro steps. If possible, I would appreciate guidance from an Apple engineer, like "This is a known issue for [list of node types]" or "Reality Composer Pro 2 is not supported for visionOS 1 development, please refer to [documentation]" or "We recommend [workaround]." Thank you.
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May ’25
Updated Object Capure -- needs LiDAR?
I have two apps released -- ReefScan and ReefBuild -- that are based on the WWDC21 sample photogrammetry apps for iOS and MacOS. Those run fine without LiDAR and are used mostly for underwater models where LiDAR does not work at all. It now appears that the updated photogrammetry session requires LiDAR data, and building my app on current xcode results in a non-working app. Has the "old" version of photgrammetry session been broken by this update? It worked very well previously so I would hate to see this regression to needing LiDAR. Most of my users do not have that.
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Mar ’25
USDZ File Crashes in QuickLook on iPad 9th Gen (iPadOS 18.3) – Urgent Help Needed
Hi everyone, I’m experiencing a critical issue with USDZ files created in Reality Composer on an iPad 9th Generation (iPadOS 18.3). The files work perfectly on iPads from the 10th Generation onwards and on iPad Pros. However, on older devices like the iPad 9th Generation and older iPhones, QuickLook (file preview) crashes when opening them. This is a major issue because these USDZ files are part of an exhibition where artworks are extended with AR elements via a web page. If some visitors cannot view the 3D content, it significantly impacts the experience. What’s puzzling is that two years ago, we exported USDZ files from Reality Composer, made them available via a website, and they worked flawlessly on all devices, including older iPads and iPhones. Now, with the latest iPadOS, they consistently crash on older devices. Has anyone encountered a similar issue? Are there known limitations with QuickLook on older devices, or is there a way to optimize the USDZ files to prevent crashes? Could this be related to changes in iPadOS or RealityKit? Any advice or workaround would be greatly appreciated! Thanks in advance!
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Feb ’25
Animating a RealityComposerPro shader's uniform input value
I'm trying to build a Shader in "Reality Composer Pro" that updates from a start time. Initially I tried the following: The idea was that when the startTime was 0, the output would be 0, but then I would set startTime from within code and this would be compared with the current GPU time, and difference used to drive another part of the shader graph: if let testEntity = root.findEntity(named: "Test"), var shaderGraphMaterial = testEntity.components[ModelComponent.self]?.materials.first as? ShaderGraphMaterial { let time = CFAbsoluteTimeGetCurrent() try! shaderGraphMaterial.setParameter(name: "StartTime", value: .float(Float(time))) testEntity.components[ModelComponent.self]?.materials[0] = shaderGraphMaterial } However, I haven't found a reference to the time the shader would be using. So now I am trying to write an EntityAction to achieve the same effect. Instead of comparing a start time to the GPU's time I'm trying to animate one of the shader's uniform input. However, I'm not sure how to specify the bind target. Here's my attempt so far: import RealityKit struct ShaderAction: EntityAction { let startValue: Float let targetValue: Float var animatedValueType: (any AnimatableData.Type)? { Float.self } static func registerEntityAction() { ShaderAction.subscribe(to: .updated) { event in guard let animationState = event.animationState else { return } let value = simd_mix(event.action.startValue, event.action.targetValue, Float(animationState.normalizedTime)) animationState.storeAnimatedValue(value) } } } extension Entity { func updateShader(from startValue: Float, to targetValue: Float, duration: Double) { let fadeAction = ShaderAction(startValue: startValue, targetValue: targetValue) if let shaderAnimation = try? AnimationResource.makeActionAnimation(for: fadeAction, duration: duration, bindTarget: .material(0).customValue) { playAnimation(shaderAnimation) } } } ''' Currently when I run this I get an assertion failure: 'Index out of range (operator[]:line 797) index = 260, max = 8' Furthermore, even if it didn't crash I don't understand how to pass a binding to the custom shader value "startValue". Any clues of how to achieve this effect - even if it's a completely different way.
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Feb ’25
alternative for CustomShader in visionOS
Following the post on https://developer.apple.com/documentation/realitykit/custommaterial it's simple to use shader for materials and get uniforms and params from each vertex. However it's not available for visionOS. Any alternative to use in this case? I want to write shader to fill material by myself. (I have shader experience from web, familiar with fragment shader)
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Feb ’25
Issue with FBX import -- models are ultra small
When importing FBX animations (generated by Cinema 4d or Blender) the models come in very far way and cannot resize or zoomed in. I have tried every setting from both programs to no avail. Is there a secret to providing the right export options? When importing without animations/and rigging the model imports fine and correct size. But once motion is included, something is awry. I also tried changing base units in Converter, but did not work. I have attache my model heirarchy in C4D as well as the imported result. It appears the animation is imported, as I can see it move, but can barely see it :)
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Feb ’25