RealityKit

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

Posts under RealityKit tag

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How to get the transform of the joint in a skeleton when it is Animating
I have an entity that was created using Mixamo, and it has an animation. after the animation completes the mesh of the robot is not where the entity is positioned. I want to do something like when the animation finishes, I set the root entity's transform to the mesh's transform. There are no transformations applied to any of the children of this root of the model, which means that the transformations are applied to the skeleton due the the playing of animations. Is there a way where I can apply the final position of the root of the skeleton to the root entity to make sure to position the entity where the animation has ended just before the next animation plays?
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May ’25
Using a WKWebView inside RealityView attachment causes crashes.
I have an attachment anchored to the head motion, and I put a WKWebView as the attachment. When I try to interact with the web view, the app crashes with the following errors: *** Assertion failure in -[UIGestureGraphEdge initWithLabel:sourceNode:targetNode:directed:], UIGestureGraphEdge.m:28 *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid parameter not satisfying: targetNode' *** First throw call stack: (0x18e529340 0x185845e80 0x192c2283c 0x2433874d4 0x243382ebc 0x2433969a8 0x24339635c 0x243396088 0x243907760 0x2438e4c94 0x24397b488 0x24397e28c 0x243976a20 0x242d7fdc0 0x2437e6e88 0x2437e6254 0x18e4922ec 0x18e492230 0x18e49196c 0x18e48bf3c 0x18e48b798 0x1d3156090 0x2438c8530 0x2438cd240 0x19fde0d58 0x19fde0a64 0x19fa5890c 0x10503b0bc 0x10503b230 0x2572247b8) libc++abi: terminating due to uncaught exception of type NSException *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid parameter not satisfying: targetNode' *** First throw call stack: (0x18e529340 0x185845e80 0x192c2283c 0x2433874d4 0x243382ebc 0x2433969a8 0x24339635c 0x243396088 0x243907760 0x2438e4c94 0x24397b488 0x24397e28c 0x243976a20 0x242d7fdc0 0x2437e6e88 0x2437e6254 0x18e4922ec 0x18e492230 0x18e49196c 0x18e48bf3c 0x18e48b798 0x1d3156090 0x2438c8530 0x2438cd240 0x19fde0d58 0x19fde0a64 0x19fa5890c 0x10503b0bc 0x10503b230 0x2572247b8) terminating due to uncaught exception of type NSException Message from debugger: killed This is the code for the RealityView struct ImmersiveView: View { @Environment(AppModel.self) private var appModel var body: some View { RealityView { content, attachments in let anchor = AnchorEntity(AnchoringComponent.Target.head) if let sceneAttachment = attachments.entity(for: "test") { sceneAttachment.position = SIMD3<Float>(0,0,-3.5) anchor.addChild(sceneAttachment) } content.add(anchor) } attachments: { Attachment(id: "test") { WebViewWrapper(webView: appModel.webViewModel.webView) } } } } This is the appModel: import SwiftUI import WebKit /// Maintains app-wide state @MainActor @Observable class AppModel { let immersiveSpaceID = "ImmersiveSpace" enum ImmersiveSpaceState { case closed case inTransition case open } var immersiveSpaceState = ImmersiveSpaceState.closed public let webViewModel = WebViewModel() } @MainActor final class WebViewModel { let webView = WKWebView() func loadViz(_ addressStr: String) { guard let url = URL(string: addressStr) else { return } webView.load(URLRequest(url: url)) } } struct WebViewWrapper: UIViewRepresentable { let webView: WKWebView func makeUIView(context: Context) -> WKWebView { webView } func updateUIView(_ uiView: WKWebView, context: Context) { } } and finally the ContentView where I added a button to load the webpage: struct ContentView: View { @Environment(AppModel.self) private var appModel var body: some View { VStack { ToggleImmersiveSpaceButton() Button("Go") { appModel.webViewModel.loadViz("http://apple.com") } } .padding() } }
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May ’25
How to add and remove child entities to a rigged entity in RealityKit?
I am currently using RealityKit (perspective camera) to render a character in my swiftUI app. The character has customization such as clothing items and hair and all objects are properly weighted to the rig. The way the model is setup in Blender is like so: Groups of objects that will be swapped (ex: Shoes -> Shoes objects) and an armature. I then export it to usdc with all objects active. This is the resulting hierarchy: Before exporting for the animation (armature modifier applied), I simply had to store the Model entities and swap them in but now when I export with the Armature Modifier applied, so that animations get exported, the ModelComponent gets flattened to the armature and swapping entities and applying new materials to them is no longer as simple. Here's a demo blend file and usdc export with a setup like mine, having an animated bone to swing a cube and sphere, to be swapped so that only one is visible https://www.dropbox.com/scl/fo/be2q6qcztc83z7c4gj1w0/AMapxWc_ip2KZ8oTOYDUMv8?rlkey=rcdaggcxq06dyen09mw5mqmem&st=bnc0d7j0&dl=0 This is how I'm loading the entity and removing a part, with the demo files import SwiftUI import RealityKit struct SwapDemoView: View { var body: some View { RealityView { content in let camera = PerspectiveCamera() camera.transform.translation = SIMD3(x: 0, y: 0.1, z: 3) guard let root = try? await Entity(named: "simpleSwapDemo") else { fatalError("simpleSwapDemo.usdc is not present") } print(root) // Get initial hierarchy guard let cube = root.findEntity(named: "Cube") else { fatalError("Entity cube doesn't exist") } cube.removeFromParent() // <-- Cube is still visible after removal print(root) // Get hierarchy to confirm removal of cube let resource = root.availableAnimations[0] root.playAnimation(resource.repeat()) content.add(root) content.add(camera) } .background(.white) } } And this is what the entity hierarchy looks like in RealityKit before cube removal ▿ 'root' : Entity, children: 1 ⟐ SynchronizationComponent ⟐ AnimationLibraryComponent ⟐ Transform ▿ 'Armature' : ModelEntity, children: 2 ⟐ SynchronizationComponent ⟐ ModelComponent ⟐ SkeletalPosesComponent ⟐ AnimationLibraryComponent ⟐ Transform ▿ 'Armature' : Entity ⟐ SynchronizationComponent ⟐ Transform ▿ 'Primitives' : Entity, children: 2 ⟐ SynchronizationComponent ⟐ Transform ▿ 'Sphere' : Entity, children: 1 ⟐ SynchronizationComponent ⟐ Transform ▿ 'Sphere' : Entity ⟐ SynchronizationComponent ⟐ Transform ▿ 'Cube' : Entity, children: 1 ⟐ SynchronizationComponent ⟐ Transform ▿ 'Cube' : Entity ⟐ SynchronizationComponent ⟐ Transform And here's the hierarchy after removal ▿ 'root' : Entity, children: 1 ⟐ SynchronizationComponent ⟐ AnimationLibraryComponent ⟐ Transform ▿ 'Armature' : ModelEntity, children: 2 ⟐ SynchronizationComponent ⟐ ModelComponent ⟐ SkeletalPosesComponent ⟐ AnimationLibraryComponent ⟐ Transform ▿ 'Armature' : Entity ⟐ SynchronizationComponent ⟐ Transform ▿ 'Primitives' : Entity, children: 1 ⟐ SynchronizationComponent ⟐ Transform ▿ 'Sphere' : Entity, children: 1 ⟐ SynchronizationComponent ⟐ Transform ▿ 'Sphere' : Entity ⟐ SynchronizationComponent ⟐ Transform And this is the result: What's the best practice here? Should animation be exported separately and then applied to the skeleton? If so, how is that achieved? I'm not really sure how to proceed here.
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May ’25
How to make .blur(radius:) visually affect RealityView content?
According to the official documentation, the .blur(radius:) modifier could apply gaussian blur to a realityview. However, when applied directly to a RealityView, nothing inside it (neither 2D attachments nor 3D entities) appears to be blurred. Here’s the test code: struct ContentView: View { var body: some View { VStack(spacing: 20) { Text("Above the RealityView") .font(.title) RealityView { content, attachments in if let text = attachments.entity(for: "2dView") { text.position.y = 0.1 content.add(text) } let box = ModelEntity( mesh: .generateBox(size: 0.1), materials: [SimpleMaterial(color: .red, isMetallic: true)] ) content.add(box) } attachments: { Attachment(id: "2dView") { Text("Above the Box") .font(.title) } } .frame(width: 300, height: 300) .border(.blue) .blur(radius: 99) // Has no visual effect Text("Below the RealityView") .font(.subheadline) } .padding() } } My question: How can I make .blur(radius:) visually affect the content rendered in a RealityView? Can you provide a working example that .blur() to visually affect any part of a RealityView? Thanks!
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May ’25
How to add visual thickness to a glass background view
Hi guys, In visionOS, when using a ZStack decorated with .glassBackgroundEffect(), you can see the 3D glass background from the front, but when viewed from the side, the view appears to have no thickness. However, I noticed that in an app built by Apple, when viewing a glass background view from the side, it appears to have thickness. I tried adding .frame(depth:) to a glass background view, but it appears as two separate layers spaced by the depth value. My question is: Is there a view modifier that adds visual thickness to a glass background view, as shown in the picture? Or, if not, how should I write a custom view modifier to achieve this effect? Thanks!
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May ’25
Transparent Material Turning into Occlusion Material
I am trying to create an object in immersive space that is partially transparent (~50% opacity). I have implemented this in a few different ways including creating a model entity and setting its opacity component to 0.5, and creating a custom material with blending set to a transparent opacity of 0.5. These both work partially, as they behaved as intended for many cases, but seemingly randomly would act like occlusion material and block any other immersive content behind them, showing the real world instead. Some notes: I am using RealityKit to render the semi-transparent object and an opaque object that is behind the semi-transparent object. I am using VisionOS 2.1, and am updating the location of the semi-transparent object often. Both objects are ModelEntities. I would appreciate any guidance on how to implement this. Please let me know if there are any other questions.
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May ’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
RealityRenderer's Perspective Camera's FOV
Hi, I have been using RealityRenderer to render scenes in MacOS as spatial videos and view it in Vision Pro and it is awesome. I understand that it uses PerspectiveCamera to render. I wanted to know what is the default FOV for this camera and how much can we push it? I want to ideally render a scene with 180 degrees of fov. Thanks
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May ’25
Launching a timeline on a specific model via notification
Hello! I’m familiar with the discussion on “Sending messages to the scene”, and I’ve successfully used that code. However, I have several instances of the same model in my scene. Is it possible to make only one specific model respond to a notification? For example, can I pass something like RealityKit.NotificationTrigger.SourceEntity in userInfo or use another method to target just one instance?
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May ’25
How to implement the semi-transparent overlay effect in Immersive View?
I noticed that when I drag the menu window in an Immersive View, the entities behind it becomes semi-transparent, and the boundary between virtual and real-world objects is very pronounced. May I ask how does VisionOS implement this effect? Is there any API or technique I can use in my own code to enable the same semi-transparent overlay - even when I am not dragging the menu window?
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May ’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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May ’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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May ’25
RealityKit System update and timing
Hi, I'm playing now with hand tracking. I want to get position of hand inside a system update function. I was not sure if transform I'm getting from hand attached AnchorEntity (with trackingMode: .predicted) would give same results as handAnchors(at:) from hand tracking provider, so I started to read them both and compare. For handAnchors i tried using context.scene.timebase.sourceTimebase!.sourceClock!.time.seconds and CACurrentMediaTime() as timestamp source. They seem to use exactly same clock, so that doesn't matter, but: for some reason update handler is always called twice with same context.deltaTime, but first time the query finds 0 entities, second time it finds them all. The query is the standard EntityQuery(where: .has(MyComponent.self)) and in update (matching: Self.query, updatingSystemWhen: .rendering). Here's part of logs: System update called, entity count: 0, dt: 0.01000458374619484, absTime: 4654.222593541 System update called, entity count: 11, dt: 0.01000458374619484, absTime: 4654.22262525 System update called, entity count: 0, dt: 0.009999999776482582, absTime: 4654.249390875 System update called, entity count: 11, dt: 0.009999999776482582, absTime: 4654.249425 accounting for the double update calling I started to calculate time delta of absolute time between calls and they're most of the time much bigger, or much smaller than advertised by system's context.deltaTime, only sometimes they kind of match, for example: system: (dt: 0.01000458374619484) scene : (dt: 0.021419291667371) (absTime: 4654.222628125001) and the very next call system: (dt: 0.010009 166784584522) scene : (dt: 0.0013097083328830195) (absTime: 4654.223937833334) but sometimes system: (dt: 0.009999999776482582) scene : (dt: 0.009 112249999816413) (absTime: 4654.351299 166668) Shouldn't those be more or less equal, or am I missing something? In the end it seems that getting hand position from AnchorEntity and with handAnchors(at:) gives kind of same results, but at different time points, so I'd love to understand what's the correct way to use them and why time flows differently :). --Edit-- P.S. Had to put spaces everywhere in logs between "9" and "1", otherwise post was blocked due to "sensitive content" :D
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May ’25
RoomPlan - The delegate of ARSession is retaining x ARFrames
Hi, I'm encountering an issue in our app that uses RoomPlan and ARsession for scanning. After prolonged use—especially under heavy load from both the scanning process and other unrelated app operations—the iPhone becomes very hot, and the following warning begins to appear more frequently: "ARSession <0x107559680>: The delegate of ARSession is retaining 11 ARFrames. The camera will stop delivering camera images if the delegate keeps holding on to too many ARFrames. This could be a threading or memory management issue in the delegate and should be fixed." I was able to reproduce this behavior using Apple’s RoomPlanExampleApp, with only one change: I introduced a CPU-intensive workload at the end of the startSession() function: DispatchQueue.global().asyncAfter(deadline: .now() + 5) { for i in 0..<4 { var value = 10_000 DispatchQueue.global().async { while true { value *= 10_000 value /= 10_000 value ^= 10_000 value = 10_000 } } } } I suspect this is some RoomPlan API problem that's why a filed an feedback: 17441091
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May ’25
Cannot reassign worldTracking / planeDetection providers in my PlacementManager when switching environments
Environment Xcode: 16.2 VisionOS SDK 2.4 Swift 6.1 Targets: Apple Vision Pro (immersive space) Frameworks: ARKit, RealityKit, SwiftUI What I’m Trying to Do I have a view-model class PlacementManager that holds two AR providers: private var worldTracking: WorldTrackingProvider private var planeDetection: PlaneDetectionProvider I want to dynamically replace these providers in a setEnvironment(_:) method (so I can save/clear a JSON scene and restart ARKit). What’s Happening If I declare them as : private let worldTracking = WorldTrackingProvider() private let planeDetection = PlaneDetectionProvider() I get compile-errors when I later do: self.worldTracking = newWorldTracking // Cannot assign to property: 'worldTracking' is a 'let' constant If I change them to un-initialized vars: private var worldTracking: WorldTrackingProvider private var planeDetection: PlaneDetectionProvider then in my init() I get: self used in property access 'worldTracking' before all stored properties are initialized Code snipet @Observable final class PlacementManager : ObservableObject { private var worldTracking: WorldTrackingProvider private var planeDetection: PlaneDetectionProvider // … other props … @MainActor init() { // error: self.worldTracking used before init… planeAnchorHandler = PlaneAnchorHandler(rootEntity: root) persistenceManager = PersistenceManager( worldTracking: worldTracking, rootEntity: root ) // … } @MainActor func setEnvironment(env: Environnement) async { let newWorldTracking = WorldTrackingProvider() let newPlaneDetection = PlaneDetectionProvider() try await appState!.arkitSession.run( [ newWorldTracking, newPlaneDetection ] ) self.worldTracking = newWorldTracking self.planeDetection = newPlaneDetection // … } } What I’ve Tried Giving them default values at declaration (= WorldTrackingProvider()) Initializing them at the top of init() before any use Passing the new providers into arkitSession.run(...) My Question What is the recommended Swift-style pattern to declare and reassign these ARKit provider properties so that: They’re fully initialized before use in init(), and I can swap them out later in setEnvironment(...) without compiler errors? Any pointers (or links to forum threads / docs) would be greatly appreciated!
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128
May ’25
Playing USDZ animation at last known location of reference object
Hi there I'm using Reality Composer Pro to anchor virtual content to a .referenceobject. However moving the referenceobject quickly causes tracking to stop. (I know this is a limitation and I am trying to embrace it as a feature) Is there a way to play a USDZ animation at the last known location, after detecting that the reference object is no longer tracked? is it possible to set this up in Reality Composer pro? I'm trying to get the USDZ to play before the Virtual Content disappears (due to reference object not being located). So that it smooths out the vanishing of the content. Nearly everything is set up in Reality Composer pro with my immersive.scene just adding virtual content to the reference object which anchors it in the RCP Scene, so my immersive view just does this - if let immersiveContentEntity = try? await Entity(named: "Immersive", in: realityKitContentBundle) { content.add(immersiveContentEntity) & this .onAppear { appModel.immersiveSpaceState = .open } .onDisappear { appModel.immersiveSpaceState = .closed } I have tried Using SpatialTracking & WorldTrackingProvider, but I'm still quite new to Swift and coding in general so im unsure how to implement in conjunction with my RCP scene and/or if this is the right way to go about it. Also I have implemented this at the beginning of object tracking. All I had to do was add a onAppear behavior to the object to play a USDZ and that works. Doing it for disappearing (due to loss of reference object) seems to be a lot harder.
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Apr ’25
Playing USDZ animation at last known location of reference object
Hi there I'm using Reality Composer Pro to anchor virtual content to a .referenceobject. However by moving the referenceobject quickly, it causes tracking to stop. (I know this is a limitation so im trying to make it a feature) IS there a way to play a USDZ animation at the last known location, after detecting that reference object is no longer being tracked? is it possible to set this up in Reality Composer pro? Nearly everything is set up in Reality Composer pro with my immersive.scene just anchoring virtual content to the Reference object in the RCP Scene, so my immersive view just does this - if let immersiveContentEntity = try? await Entity(named: "Immersive", in: realityKitContentBundle) { content.add(immersiveContentEntity) & this .onAppear { appModel.immersiveSpaceState = .open } .onDisappear { appModel.immersiveSpaceState = .closed } I have tried Using SpatialTracking & WorldTrackProvider, but I'm still quite new to Swift and coding in general so im unsure how to implement in conjunction with my RCP scene and if this is actually the right way to do it. Apologies for my lack of knowledge.
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86
Apr ’25
Unity PolySpatial – Live handheld camera feed of graspable objects not rendering on Vision Pro
I am developing a Unity application for the Apple Vision Pro using PolySpatial and RealityKit integration. The goal is to create a graspable object (for example, a handheld cube) that includes a secondary camera. When the user grabs and moves the object, the secondary camera should render its view to a RenderTexture, which is displayed on a quad attached to the object, simulating a live camera screen. In the Unity Editor, this setup works correctly. The RenderTexture updates in real time, and the quad displays the camera’s view as expected. However, when building and running the application on the Vision Pro, the quad only displays the clear background color of the secondary camera. No scene content appears. The graspable interaction itself works fine: the object can be grabbed and moved as intended. Steps I have taken: Created a new layer (CameraFeed) and assigned the relevant objects to it. Set the secondary camera’s culling mask to render only the CameraFeed layer. Assigned the RenderTexture as the camera’s target texture. Applied the RenderTexture to an Unlit/Texture material on a quad. Confirmed the camera is active and correctly positioned relative to the object. From my research, it appears that once objects are managed by RealityKit through PolySpatial (for example, made graspable), they are no longer rendered through Unity's normal camera pipeline. Only the main XR camera (managed by RealityKit) seems able to see these objects. Secondary Unity cameras cannot render RealityKit-synced content to a RenderTexture. If this is correct, it seems there is currently no way to implement a true live secondary camera feed showing graspable objects on Vision Pro using Unity PolySpatial. My questions are: Is there any official way to enable multiple camera rendering of RealityKit-managed objects through PolySpatial? Are there known workarounds to simulate a live camera feed that still allows objects to be grabbed? Has anyone found alternative design patterns or methods for this kind of interaction? Environment: Unity 6.0 , PolySpatial 2.2.4, Apple Vision OS XR 2.2.4 Any insight or suggestions would be greatly appreciated. Thank you.
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116
Apr ’25
RealityView in UIHostingController/UIKit transparency
I'm experimenting with RealityView in the UI of an AUv3 plug-in. The plug-in UI is implemented in a UIKitViewController with a UIHostingController hosting a RealityView. When i run the standalone app on visionOS I want the background to be transparent, and the reality view content. how can i achieve that? I've tried turning off opaque in many views and and setting background colors to .clear.
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Apr ’25