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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moveCharacter reports collision with itself
I'm running into an issue with collisions between two entities with a character controller component. In the collision handler for moveCharacter the collision has both hitEntity and characterEntity set to the same object. This object is the entity that was moved with moveCharacter() The below example configures 3 objects. stationary sphere with character controller falling sphere with character controller a stationary cube with a collision component if the falling sphere hits the stationary sphere then the collision handler reports both hitEntity and characterEntity to be the falling sphere. I would expect that the hitEntity would be the stationary sphere and the character entity would be the falling sphere. if the falling sphere hits the cube with a collision component the the hit entity is the cube and the characterEntity is the falling sphere as expected. Is this the expected behavior? The entities act as expected visually however if I want the spheres to react differently depending on what character they collided with then I am not getting the expected results. IE: If a player controlled character collides with a NPC then exchange resource with NPC. if player collides with enemy then take damage. import SwiftUI import RealityKit struct ContentView: View { @State var root: Entity = Entity() @State var stationary: Entity = createCharacter(named: "stationary", radius: 0.05, color: .blue) @State var falling: Entity = createCharacter(named: "falling", radius: 0.05, color: .red) @State var collisionCube: Entity = createCollisionCube(named: "cube", size: 0.1, color: .green) //relative to root @State var fallFrom: SIMD3<Float> = [0,0.5,0] var body: some View { RealityView { content in content.add(root) root.position = [0,-0.5,0.0] root.addChild(stationary) stationary.position = [0,0.05,0] root.addChild(falling) falling.position = fallFrom root.addChild(collisionCube) collisionCube.position = [0.2,0,0] collisionCube.components.set(InputTargetComponent()) } .gesture(SpatialTapGesture().targetedToAnyEntity().onEnded { tap in let tapPosition = tap.entity.position(relativeTo: root) falling.components.remove(FallComponent.self) falling.teleportCharacter(to: tapPosition + fallFrom, relativeTo: root) }) .toolbar { ToolbarItemGroup(placement: .bottomOrnament) { HStack { Button("Drop") { falling.components.set(FallComponent(speed: 0.4)) } Button("Reset") { falling.components.remove(FallComponent.self) falling.teleportCharacter(to: fallFrom, relativeTo: root) } } } } } } @MainActor func createCharacter(named name: String, radius: Float, color: UIColor) -> Entity { let character = ModelEntity(mesh: .generateSphere(radius: radius), materials: [SimpleMaterial(color: color, isMetallic: false)]) character.name = name character.components.set(CharacterControllerComponent(radius: radius, height: radius)) return character } @MainActor func createCollisionCube(named name: String, size: Float, color: UIColor) -> Entity { let cube = ModelEntity(mesh: .generateBox(size: size), materials: [SimpleMaterial(color: color, isMetallic: false)]) cube.name = name cube.generateCollisionShapes(recursive: true) return cube } struct FallComponent: Component { let speed: Float } struct FallSystem: System{ static let predicate: QueryPredicate<Entity> = .has(FallComponent.self) && .has(CharacterControllerComponent.self) static let query: EntityQuery = .init(where: predicate) let down: SIMD3<Float> = [0,-1,0] init(scene: RealityKit.Scene) { } func update(context: SceneUpdateContext) { let deltaTime = Float(context.deltaTime) for entity in context.entities(matching: Self.query, updatingSystemWhen: .rendering) { let speed = entity.components[FallComponent.self]?.speed ?? 0.5 entity.moveCharacter(by: down * speed * deltaTime, deltaTime: deltaTime, relativeTo: nil) { collision in if collision.hitEntity == collision.characterEntity { print("hit entity has collided with itself") } print("\(collision.characterEntity.name) collided with \(collision.hitEntity.name) ") } } } } #Preview(windowStyle: .volumetric) { ContentView() }
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161
Aug ’25
Regression: RealityKit spatial audio crackles and pops on iOS 26.0 beta 5 (FB19423059)
RealityKit spatial audio crackles and pops on iOS 26.0 beta 5. It works correctly on iOS 18.6 and visionOS 26.0 beta 5. The APIs used are AudioPlaybackController, Entity.prepareAudio, Entity.play Videos of the expected and observed behavior are attached to the feedback FB19423059. The audio should be a consistent, repeating sound, but it seems oddly abbreviated and the volume varies unexpectedly. Thank you for investigating this issue.
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Aug ’25
PhotogrammetrySession fails with internal errors 4011 / 4012 when using iOS Object Capture (Area Mode) images
Hi all, I’m running into an issue when trying to reconstruct a 3D model using PhotogrammetrySession on macOS from a set of images captured via the iOS Object Capture sample app, specifically in Area mode. When I attempt to create the model from these images (using the raw Images/ folder exported directly from the capture session), I get the following errors: ERROR cv3dapi.pg: Internal error codes (2): 4011 4012 WARN cv3dapi.pg: Internal warning codes (1): 4507 Output error with code = -15 requestError: CoreOC.PhotogrammetrySession.Error.processError I use the "Images" directory directly exported from Object Capture with my iphone 12 pro max (has lidar) set to "area mode" in the object capture app here is an example heic image metadata from the sequence. heif-info Images/00044.869568833.HEIC MIME type: image/heic main brand: heic compatible brands: mif1, MiHE, MiPr, miaf, MiHB, heic image: 3024x4032 (id=49), primary tiles: 6x8, tile size: 512x512 colorspace: YCbCr, 4:2:0 bit depth: 8 thumbnail: 240x320 color profile: nclx alpha channel: no depth channel: yes size: 192x256 bits per pixel: 8 z-near: 1.173828 z-far: 2.552734 d-min: undefined d-max: undefined representation: uniform Z metadata: Exif: 960 bytes uri /tag:apple.com,2023:ObjectCapture#CameraTrackingState: 4 bytes uri /tag:apple.com,2023:ObjectCapture#CameraCalibrationData: 1015 bytes uri /tag:apple.com,2023:ObjectCapture#ObjectTransform: 48 bytes uri /tag:apple.com,2023:ObjectCapture#ObjectBoundingBox: 48 bytes uri /tag:apple.com,2023:ObjectCapture#RawFeaturePoints: 832 bytes uri /tag:apple.com,2023:ObjectCapture#PointCloudData: 23984 bytes uri /tag:apple.com,2023:ObjectCapture#BundleVersion: 5 bytes uri /tag:apple.com,2023:ObjectCapture#SegmentID: 4 bytes uri /tag:apple.com,2024:ObjectCapture#SessionUUID: 36 bytes uri /tag:apple.com,2024:ObjectCapture#CaptureMode: 4 bytes uri /tag:apple.com,2023:ObjectCapture#Feedback: 4 bytes uri /tag:apple.com,2023:ObjectCapture#WideToDepthCameraTransform: 48 bytes uri /tag:apple.com,2023:ObjectCapture#TemporalDepthPointClouds: 864026 bytes transformations: angle (ccw): 270 region annotations: none properties: camera intrinsic matrix: focal length: 2813.695557; 2813.695557 principal point: 1522.338502; 2002.843018 skew: 0.000000 camera extrinsic matrix: rotation matrix: -0.695 0.344 -0.632 0.007 -0.875 -0.483 -0.719 -0.340 0.606 Questions: • What do internal error codes 4011 and 4012 refer to? • Is there something specific about Area mode captures that require preprocessing before they’re compatible with PhotogrammetrySession? • Has anyone successfully reconstructed a model from an Area mode session using the stock Apple tools? NOTE: I can provide the folder of images for debugging if that would help!
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Jul ’25
Struggles with attaching a ModelEntity to the skeleton joints of another ModelEntity
In SceneKit, when creating an .scn file from a rigged model, the framework created an SCNNode for each bone/joint, so you could add and remove child nodes directly to and from joints, and like any other SCNNode, you could access world position and world orientation for each joint. The analog would be for joints to be accessible as child entities of a ModelEntity in RealityKit. I am unable to proceed with migrating my project from SceneKit because of this, as there does not seem to be a way to even access the true world position of a joint with the current jointNames/jointTransforms paradigm. The translation information from the given transforms is insufficient to determine the location of a joint at any given time, and other approaches like creating a GeometricPin for the given joint name and attaching it to another entity do not seem to work. So conveniently being able to attach an item to the hand of a rigged model was trivial in SceneKit and now feels impossible in RealityKit. I am not the first person to notice this, and am feeling demoralized about proceeding with RealityKit with such a critical piece of functionality blocked https://stackoverflow.com/questions/76726241/how-do-i-attach-an-entity-to-a-skeletons-joint-in-realitykit Will this be addressed in some way?
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765
Jul ’25
BlendShapes don’t animate while playing animation in RealityKit
Hi everyone, I’m running into an issue with RealityKit when trying to animate BlendShapes (ShapeKeys) while a skeletal animation is playing. The model is a rigged character in .usdz format with both predefined skeletal animations and BlendShapes (exported from Blender). The problem: when I play any animation using entity.playAnimation(...), the BlendShapes stop responding. Calling setBlendShapes(...) still logs that weights are being updated, but the visual changes are not visible. The exact same blend shape animation works perfectly when no animation is playing. In SceneKit the same model works as expected: shape keys get animated during animation playback. But not in realitykit Still, as soon as an animation starts, the shape keys don’t animate anymore. Here’s the test project on GitHub that demonstrates the issue clearly: https://github.com/IAMTHEBURT/RealityKitWitnBlendShapesSample The goal is to play facial expressions (like blinking or talking) while a body animation (like waving) is playing. Is this a known limitation in RealityKit? Or is there a recommended way to combine skeletal animations with real-time BlendShape updates? Thanks in advance for any insights.
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Jul ’25
RealityKit generates an excessive amount of logging
During regular use, RealityKit generates an excessive amount of internal logging that is not actionable by third party developers. When developing an iOS RealityKit/ARKit app, this makes the Xcode console challenging to use for regular work. (FB19173812) See screenshots below. Xcode does have an option for filtering out logging from specific SDKs, but enabling this feature to suppress the logging of RealityKit and related SDKs like PHASE is something developers have to do dozens of times each day. After a year of developing a RealityKit app, this process becomes frustrating. If SDKs like Foundation, UIKit, and SwiftUI generated as much logging as RealityKit and related SDKs, Xcode's console would be unusable. Is there any way to disable the logging of RealityKit and PHASE permanently? Thank you for any help you provide.
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Jul ’25
GestureComponent does not support DragGesture
The following code using the new GestureComponent demonstrates inconsistency. The tap gesture prints output, but the drag gesture does not. I already checked this post, which points to this seemingly outdated sample code I assume that example is deprecated in favour of the now built in version of GestureComponent. Nonetheless, there are no compiler warnings or errors, it just fails silently. TapGesture, LongPressGesture, MagnifyGesture, RotateGesture all work, so this feels like an oversight. RealityView { content in let testEntity = ModelEntity(mesh: .generateBox(size: .init(x: 1, y: 1, z: 1))) testEntity.position = SIMD3<Float>(0,0,-1) testEntity.components.set(InputTargetComponent()) testEntity.components.set(CollisionComponent( shapes: [.generateBox(size: .init(x: 1, y: 1, z: 1))] )) let testGesture = TapGesture() .onEnded { value in print("Tapped") } testEntity.components.set(GestureComponent(testGesture)) let dragGesture = DragGesture() .onEnded { value in print("Dragged") } testEntity.components.set(GestureComponent(dragGesture)) content.add(testEntity) }
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Jul ’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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358
Jul ’25
How to Configure angularLimitInYZ for PhysicsSphericalJoint in RealityKit (Pendulum/Swing Behavior)
Hello RealityKit developers, I'm currently working on physics simulations in my visionOS app and am trying to adapt the concepts from the official sample Simulating physics joints in your RealityKit app. In the sample, a sphere is connected to the ceiling using a PhysicsRevoluteJoint to create a hinge-like simulation. I've successfully modified this setup to use a PhysicsSphericalJoint instead. The basic replacement works as expected: pin1 (attached to the sphere) rotates freely around pin0 (attached to the ceiling), much like a ball-and-socket joint should, removing all translational degrees of freedom. My challenge lies with the PhysicsSphericalJoint's angularLimitInYZ property. The documentation mentions that this property allows limiting the rotation around the Y and Z axes, defining an "elliptical cone shape around the x-axis of pin0." However, I'm struggling to understand how to specify these values to achieve a desired rotational limit. If I have a sphere that is currently capable of rotating 360 degrees around pin0 (like a free-spinning ball on a string), how would I use angularLimitInYZ to restrict its rotation to a certain height or angular range, preventing it from completing a full circle? Specifically, I'm trying to achieve a "swing" like behavior where the sphere oscillates back and forth but cannot rotate completely overhead or underfoot. What values or approach should I use for the angularLimitInYZ tuple to define such a restricted pendulum-like motion? Any insights, code examples, or explanations on how to properly configure angularLimitInYZ for this kind of behavior would be incredibly helpful! The following code is modified from the sample. extension MainView { func addPinsTo(ballEntity: Entity, attachmentEntity: Entity) throws { let hingeOrientation = simd_quatf(from: [1, 0, 0], to: [0, 0, 1]) let attachmentPin = attachmentEntity.pins.set( named: "attachment_hinge", position: .zero, orientation: hingeOrientation ) let relativeJointLocation = attachmentEntity.position( relativeTo: ballEntity ) let ballPin = ballEntity.pins.set( named: "ball_hinge", position: relativeJointLocation, orientation: hingeOrientation ) // Create a PhysicsSphericalJoint between the two pins. let revoluteJoint = PhysicsSphericalJoint(pin0: attachmentPin, pin1: ballPin) try revoluteJoint.addToSimulation() } } The following image is a screenshot of the operation when changing to PhysicsSphericalJoint. Thank you in advance for your assistance.
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264
Jul ’25
RealityKit and Reality Composer Pro aren't forward or backward compatible with each other
TL;DR: RealityKit and Reality Composer Pro aren't forward or backward compatible with each other, and the resulting error message is terse and unhelpful. (FB14828873) So far, I've been sticking with Xcode 16.4 for development and only using Xcode 26.0 beta experimentally. Yesterday, I used xcode-select to switch to Xcode 26.0 beta 3 to test it, but I forgot to switch back. Consequently, this morning I unintentionally used the future Reality Composer Pro (the version included with Xcode 26) to make a small change to a USD file. Now I realize that if I'm unlucky, it's possible Reality Composer Pro may have silently introduced a small change into the USD file that may make RealityKit fail to read the file on iOS 18 and visionOS 2, which in the past has resulted in hours of debugging to track down the source of the failure, often a single line in the USD file that RealityKit can't communicate to me other than with the error "the operation couldn't be completed". As an analogy, this situation is as if, during regular development (not involving Reality Composer Pro), Xcode didn't warn you about specific API version conflicts, but instead failed with a generic error message, without highlighting the line in your Swift file that was the source of the error.
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Jul ’25
How to implement c for vision ?
I want to use reality to create a custom material that can use my own shader and support Mesh instancing (for rendering 3D Gaussian splating), but I found that CustomMaterial does not support VisionOS. Is there any other interface that can achieve my needs? Where can I find examples?
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81
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
Why Large-Scale Model Scenes Cause Real Device Crashes
Is there any limitation in Vision Pro when loading scenes with large-scale models? ​Test Case: Asset: Composite USDA file containing ​10 individual models​ (total triangles count: ~4.2M) Simulator: Loads and renders correctly Real Device: Loads asset successfully but ​ failure during rendering phase: Environment abruptly dims System spontaneously reboots How can we resolve this issue? Below are excerpted logs preceding the crash: <<<< FigAudioSession(AV) >>>> audioSessionAVAudioSession_CopyMXSessionProperty signalled err=-19224 (kFigAudioSessionError_UnsupportedOperation) (getMXSessionProperty unsupported) at FigAudioSession_AVAudioSession.m:606 Attempted to add ornament: <MRUIPlatterOrnament: 0x10a658f00; _isInternal: YES; _displaceWindowChrome: NO; _canCaptureUI: NO; _isBeingRemoved: NO; contentAnchorPoint3D: "{0.5, 0.5, 0}"; position: <MRUIPlatterOrnamentRelativePosition: 0x105b68e70; anchorPoint: {0.5, 0.5, 1}>; rotation: "{{0, 0, 0}, 0}"; opacity: 1.000000; canFollowUser: YES; effectiveOffset: "{0, 0, 0}"; presentingViewController: 0x0; billboardingBehavior: 0x0; scalingBehavior: 0x0; relativeToParent: NO; nonHeritableDepthDisplacement: 0.000000; order: 0.000000; _window._determinedSize: {0, 0}; _window: (null)> to nil or non-supporting UIScene: <UIWindowScene: 0x10a8a0000; role: UISceneSessionRoleImmersiveSpaceApplication; persistentIdentifier: test.test:SFBSystemService-BA3A21A3-D1AB-42E2-8AF0-AE0AB83BE528; activationState: UISceneActivationStateUnattached>. No action taken. Failed to set dependencies on asset 2823930584475958382 because NetworkAssetManager does not have an asset entity for that id. apply fence tx failed (client=0x98490e18) [0x10000003 (ipc/send) invalid destination port] Failed to commit transaction (client=0xa86516e2) [0x10000003 (ipc/send) invalid destination port]
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Jul ’25
How to customize shader code for visionos ?
Hello experts, I'm trying to implement a material with custom shader code, but I saw that visionOS doesn't allow you to inject custom Metal functions or use CustomMaterial like iOS/macOS, nor can you directly write Metal Shading Language (.metal) and use it through ShaderGraphMaterial. So my question is, if i want to implement your own shader code, how should i do it?
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464
Jul ’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
RealityKit not behaving as expected
This week, I developed a small multiplatform RealityKit project. I also created a demo scene in Reality Composer Pro. Afterward, I imported the local package into the project. Running the project on macOS works perfectly. However, when I tried to run it on my iPhone, I encountered a permission error indicating that it couldn’t read the package. This seems unusual to me because I assumed that the dependency is bundled into the binary file. In an attempt to resolve the issue, I pushed the RCP package to GitHub, hoping it would work. Fortunately, everything compiles successfully now, but the loading time is significantly long, and the animations don’t play on tap gestures. Could someone please help me identify the root cause of this problem?
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332
Jul ’25
ShaderGraphMaterial.getParameter(handle:) always return nil, is this expected behavior?
I've loaded a ShaderGraphMaterial from a RealityKit content bundle and I'm attempting to access the initial values of its parameters using getParameter(handle:), but this method appears to always return nil: let shaderGraphMaterial = try await ShaderGraphMaterial(named: "MyMaterial", from: "MyFile") let namedParameterValue = shaderGraphMaterial.getParameter(name: "myParameter") // This prints the value of the `myParameter` parameter, as expected. print("namedParameterValue = \(namedParameterValue)") let handle = ShaderGraphMaterial.parameterHandle(name: "myParameter") let handleParameterValue = shaderGraphMaterial.getParameter(handle: handle) // Expected behavior: prints the value of the `myParameter` parameter, as above. // Observed behavior: prints `nil`. print("handleParameterValue = \(handleParameterValue)") Is this expected behavior? Based on the documentation at https://developer.apple.com/documentation/realitykit/shadergraphmaterial/getparameter(handle:) I'd expect getParameter(handle:) to return the value of the parameter, just as getParameter(name:) does. I've tested this on iOS 18.5 and iOS 26.0 beta 2. Assuming this getParameter(handle:) works as designed, is the following ShaderGraphMaterial extension an appropriate workaround, or can you recommend a better approach? Thank you. public extension ShaderGraphMaterial { /// Reassigns the values of all named material parameters using the handle-based API. /// /// This works around an issue where, at least as of RealityKit 26.0 beta 2 and /// earlier, `getParameter(handle:)` will always return `nil` when used to read the /// initial value of a shader graph material parameter read using /// `ShaderGraphMaterial(named:from:in:)`, whereas `getParameter(name:)` will work /// as expected. private mutating func copyNamedParametersToHandles() { for parameterName in self.parameterNames { if let value = self.getParameter(name: parameterName) { let handle = ShaderGraphMaterial.parameterHandle(name: parameterName) do { try self.setParameter(handle: handle, value: value) } catch { assertionFailure("Cannot set parameter value") } } } } }
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357
Jun ’25
Sample code for WWDC25 Session
Hi! I watched the WWDC25 session "Bring your SceneKit project to RealityKit" which seemed like a great resource for those of us transitioning from the now-deprecated SceneKit framework. The session mentioned that the full sample code for the project would be available to download, but I haven't been able to find it in the Code section of the video page or in the Sample Code Library. Has the sample code been released yet? Having the project code would make it much easier to follow along with the RealityKit changes shown in the video. Thanks again for the great session.
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Jun ’25