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 Export OBJ with Texture (JPG + MTL) from ARKit LiDAR Scan in iOS?
I am using ARKit with RealityKit to scan objects using LiDAR on iOS. I can generate an OBJ file from ARMeshAnchors, but I am missing the texture export (JPG + MTL). What I Have So Far: Successfully capturing mesh using ARMeshAnchor. Converting mesh into MDLAsset and exporting .obj. I need help generating the .jpg texture and linking it to the .mtl file. private func exportScannedObject() { guard let camera = arView.session.currentFrame?.camera else { return } func convertToAsset(meshAnchors: [ARMeshAnchor]) -> MDLAsset? { guard let device = MTLCreateSystemDefaultDevice() else {return nil} let asset = MDLAsset() for anchor in meshAnchors { let mdlMesh = anchor.geometry.toMDLMesh(device: device, camera: camera, modelMatrix: anchor.transform) // Apply a gray material to the mesh let material = MDLMaterial(name: "GrayMaterial", scatteringFunction: MDLScatteringFunction()) material.setProperty(MDLMaterialProperty(name: "baseColor", semantic: .baseColor, float3: SIMD3(0.5, 0.5, 0.5))) // Gray color if let submeshes = mdlMesh.submeshes as? [MDLSubmesh] { for submesh in submeshes { submesh.material = material } } asset.add(mdlMesh) } return asset } func export(asset: MDLAsset) throws -> URL { let directory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first! let url = directory.appendingPathComponent("scaned.obj") if MDLAsset.canExportFileExtension("obj") { do { try asset.export(to: url) return url } catch let error { fatalError(error.localizedDescription) } } else { fatalError("Can't export USD") } } if let meshAnchors = arView.session.currentFrame?.anchors.compactMap({ $0 as? ARMeshAnchor }), let asset = convertToAsset(meshAnchors: meshAnchors) { do { let url = try export(asset: asset) showScanPreview(url) } catch { print("export error") } } } extension ARMeshGeometry { func vertex(at index: UInt32) -> SIMD3<Float> { assert(vertices.format == MTLVertexFormat.float3, "Expected three floats (twelve bytes) per vertex.") let vertexPointer = vertices.buffer.contents().advanced(by: vertices.offset + (vertices.stride * Int(index))) let vertex = vertexPointer.assumingMemoryBound(to: SIMD3<Float>.self).pointee return vertex } // helps from StackOverflow: // https://stackoverflow.com/questions/61063571/arkit-3-5-how-to-export-obj-from-new-ipad-pro-with-lidar func toMDLMesh(device: MTLDevice, camera: ARCamera, modelMatrix: simd_float4x4) -> MDLMesh { func convertVertexLocalToWorld() { let verticesPointer = vertices.buffer.contents() for vertexIndex in 0..<vertices.count { let vertex = self.vertex(at: UInt32(vertexIndex)) var vertexLocalTransform = matrix_identity_float4x4 vertexLocalTransform.columns.3 = SIMD4<Float>(x: vertex.x, y: vertex.y, z: vertex.z, w: 1) let vertexWorldPosition = (modelMatrix * vertexLocalTransform).columns.3 let vertexOffset = vertices.offset + vertices.stride * vertexIndex let componentStride = vertices.stride / 3 verticesPointer.storeBytes(of: vertexWorldPosition.x, toByteOffset: vertexOffset, as: Float.self) verticesPointer.storeBytes(of: vertexWorldPosition.y, toByteOffset: vertexOffset + componentStride, as: Float.self) verticesPointer.storeBytes(of: vertexWorldPosition.z, toByteOffset: vertexOffset + (2 * componentStride), as: Float.self) } } convertVertexLocalToWorld() let allocator = MTKMeshBufferAllocator(device: device); let data = Data.init(bytes: vertices.buffer.contents(), count: vertices.stride * vertices.count); let vertexBuffer = allocator.newBuffer(with: data, type: .vertex); let indexData = Data.init(bytes: faces.buffer.contents(), count: faces.bytesPerIndex * faces.count * faces.indexCountPerPrimitive); let indexBuffer = allocator.newBuffer(with: indexData, type: .index); let submesh = MDLSubmesh(indexBuffer: indexBuffer, indexCount: faces.count * faces.indexCountPerPrimitive, indexType: .uInt32, geometryType: .triangles, material: nil); let vertexDescriptor = MDLVertexDescriptor(); vertexDescriptor.attributes[0] = MDLVertexAttribute(name: MDLVertexAttributePosition, format: .float3, offset: 0, bufferIndex: 0); vertexDescriptor.layouts[0] = MDLVertexBufferLayout(stride: vertices.stride); let mesh = MDLMesh(vertexBuffer: vertexBuffer, vertexCount: vertices.count, descriptor: vertexDescriptor, submeshes: [submesh]) return mesh } } What I Need Help With: How do I generate the JPG texture from the AR scene? How do I save an MTL file linking the OBJ model to the texture? How can I correctly apply the texture when viewing the OBJ in an external 3D viewer? I appreciate any guidance, including sample code or resources! If you have a complete working solution, I’d love to discuss further via private channels.
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Feb ’25
RealityView IOS Navigation
I have a visionOS app that I’m adding support for IOS and will like to keep using RealityView. I know there are the following modifiers to add some navigation .realityViewCameraControls(.orbit) .realityViewCameraControls(.dolly) .realityViewCameraControls(.pan) But how can I add more than one? For example I would like to orbit with one finger, Pan with 2 fingers and dolly by pinching. Is this possible and if so can someone share some sample code on how to achieve that? Thanks, Guillermo
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Feb ’25
Building a custom render pipeline with RealityKit
Hello experts, and question seekers, I have been trying to get Gaussian splats working with RealityKit, however it seems not to work out for me. The library I use for Gaussian splatting: https://github.com/scier/MetalSplatter My idea was to use the renderers provided by RealityKit (aka RealityRenderer) https://developer.apple.com/documentation/realitykit/realityrenderer and the renderer provided by MetalSplatter (aka. SplatRenderer) https://github.com/scier/MetalSplatter/blob/main/MetalSplatter/Sources/SplatRenderer.swift Then with a custom render pipeline, I would be able to compose the outputs of the renderers, enabling the possibility, for example to build immersive scenery with realistic environment scans, as Gaussian splats, and RealityKit to provide the necessary features to build extra scenery around Gaussian splats, eg. dynamic 3D models inside Gaussian splats. However the problem is, as of now I am not able to do that with the current implementation of RealityRenderer. It seems to be, that first RealityRenderer is supposed to be an API, just to render colour information onto a texture, which in first glance might be useful, but misses important information, such as for example depth, and stencil information. Second issue is, even with that in mind, currently I am not able to execute RealityRenderer.updateAndRender, due to the following error messages: Could not resolve material name 'engine:BuiltinRenderGraphResources/Common/realityRendererBackground.rematerial' in bundle at '/Users//Library/Developer/CoreSimulator/Devices//data/Containers/Bundle/Application//.app'. Loading via asset path. exiting spatial tracking service update thread because wait returned 37” I was able to build a custom Metal view with UIViewRepresentable, MTKView, and MTKViewDelegate, enabling me to build a custom rendering pipeline, by utilising some of the Metal developer workflows. Reference: https://developer.apple.com/documentation/xcode/metal-developer-workflows/ Inside draw(in view: MTKView), in a class derived by MTKViewDelegate: guard let currentDrawable = view.currentDrawable else { return } let realityRenderer = try! RealityRenderer() try! realityRenderer.updateAndRender(deltaTime: 0.0, cameraOutput: .init(.singleProjection(colorTexture: currentDrawable.texture)), whenScheduled: { realityRenderer in print("Rendering scheduled") }, onComplete: { RealityRenderer in print("Rendering completed") }) Can you please tell me, what I am doing wrong? Is there any solution, that enables me to use RealityKit with for example Gaussian splats? Any help is greatly appreciated. All the best, Ethem Kurt
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Feb ’25
Subdivision shows in RealityComposerPro but not when loaded in Simulator
Hello, I am trying to use the subdivision mesh rendering option. I can see it working in RealityComposerPro: But not when loading asset and displaying in Simulator: Using this code: import SwiftUI import RealityKit import RealityKitContent struct AirspaceView: View { // MARK: - VIEW BODY var body: some View { RealityView { content in if let a = try? await Entity(named: "Models/Test/Test.usdc", in: realityKitContentBundle) { content.add(a) } } } } Any ideas why?
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Feb ’25
Entity HoverEffect Fired When inside Another Entity Collider
Hi folks, I’m new to Vision Pro stack, still trying to learn all the nuances. Here is a problem I can’t seem to find an answer. I placed entity A( a small .02 radius sphere) inside entity B( size:.1 box). Both entities have HoverEffectComponent, and both inputcomponent is set to .direct. Entity A is NOT a child of Entity B. When I direct touch Entity B, I noticed that Entity A’s hover effect is fired as well. This only happens if Entity A‘s position is inside Entity B. The gesture that is only targeted at Entity A doesn’t work either. I double checked Entity A collider which sits inside entity B collider, my direct touch shouldn’t have trigger its hove effect. Having one collider inside another seems to produce unpredictable behavior? Thanks in advance 🙏🙏🙏 Context: I’m trying to create an invisible bound around Entity A, so when my hand approaches the bound to grab Entity A, a nice spotlight hover effect would fire first on the bound before hand reaching entity A.
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Feb ’25
Setting clip shape of a RealityView
I am following this example to create a stereoscopic image: https://developer.apple.com/documentation/visionos/creating-stereoscopic-image-in-visionos I would also like to add corner radius to the stereoscopic RealityView. With ordinary SwiftUI views, we typically just use .clipShape(RoundedRectangle(cornerRadius: 32)): struct StereoImage: View { var body: some View { let spacing: CGFloat = 10.0 let padding: CGFloat = 40.0 VStack(spacing: spacing) { Text("Stereoscopic Image Example") .font(.largeTitle) RealityView { content in let creator = StereoImageCreator() guard let entity = await creator.createImageEntity() else { print("Failed to create the stereoscopic image entity.") return } content.add(entity) } .frame(depth: .zero) } .padding(padding) .clipShape(RoundedRectangle(cornerRadius: 32)) // <= HERE! } } This doesn't seem to actually clip the RealityView shown in the sample above. I am guessing this is due to the fact that the box in the RealityView has a non-zero z scale, which means it isn't on the same "layer" as its SwiftUI containers, and thus isn't clipped by the modifiers apply to the containers. How can I properly apply a clipshape to RealityViews like this? Thanks!
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Feb ’25
How to move a camera in immersive space and render its output on 2D window using RealityKit
I'm trying to develop an immersive visionOS app, which you can move an Entity having a PerspectiveCamera as its child in immersive space, and render the camera view on 2D window. According to this thread, this seems to can be achieved using RealityRenderer. But when I added the scene entity loaded from realityKitContentBundle to realityRenderer.entities, I needed to clone all entities of the scene, otherwise all entities in the immersive space will disappear. @Observable @MainActor final class OffscreenRenderModel { private let renderer: RealityRenderer private let colorTexture: MTLTexture init(scene: Entity) throws { renderer = try RealityRenderer() // If not clone entities in the scene, all entities in the immersive space will disappear renderer.entities.append(scene.clone(recursive: true)) let camera = PerspectiveCamera() renderer.activeCamera = camera renderer.entities.append(camera) ... } } Is this the expected behavior? Or is there any other way to do this (move camera in immersive space and render its output on 2D window)? Here is my sample code: https://github.com/TAATHub/RealityKitPerspectiveCamera
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Feb ’25
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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Feb ’25
SCNCamera SSAO on visionOS
Hi Looking at the documentation for screenSpaceAmbientOcclusionIntensity, I noticed that it says this is supported on visionOS 1.0+: https://developer.apple.com/documentation/scenekit/scncamera/screenspaceambientocclusionintensity Could someone enlighten me as to how that would work? As far as I know, we don't use an SCNCamera on visionOS. So, what's the idea here? Can we activate SSAO on visionOS?
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Feb ’25
How to prevent system windows occlusion when using OcclusionMaterial
We use SceneReconstructionProvider to detect meshes in the surrounding environment and apply an OcclusionMaterial to them. // Assuming `entity` represents one of the detected mesh in the environment entity.components.set(ModelComponent( mesh: mesh, materials: [OcclusionMaterial()] )) While this correctly occludes entities placed in the immersive space, it also occludes system windows. This becomes problematic when a window is dragged into an occluded area (before or after entering the immersive space), preventing interaction with its elements. In some cases, it also makes it impossible to focus on the window’s drag handle, since this might become occluded as well after moving the window nearby. More generally, system windows can be occluded when they come into proximity with a model that has OcclusionMaterial applied. I'm aware of a change introduced in visionOS 2 regarding how occlusions interact with UI elements (as noted in the release notes). I believe this change was intended to ensure windows do not remain visible when opened in another room. However, this also introduces some challenges, as described in the scenario above. Is there a way to prevent system window occlusion while still allowing entities to be occluded by environmental features? Perhaps not using OcclusionMaterial at all? Development environment: Xcode 16.2, macOS 15.2 Run-time configuration: visionOS 2.2 and 2.3
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Feb ’25
How to set Reality Composer Pro Entity/Anchor Transform/Position? iOS
I am at a loss. I have looked at examples, and I have used chat/cursor. I cannot figure out how to target the transform/position of a Reality Composer Pro project when adding it to an ARView in iOS. I have a test red sphere working perfectly for raycast positioning. When I pass the same variables (tested with print out) to the Entity or Anchor position/transform nothing changes. It seems that, no matter what, the content of the Reality Composer Pro project is placed where the camera view initialized. How do I actually interact with its position? I just want to be able to tap the screen and place the RCP wherever I want.
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Feb ’25
dyld: Symbol not found ... certain MeshResource APIs on iOS 17.x
I submitted feedback as FB16463501 -- posting here for others to see, or maybe for Apple to share any help if there are workarounds, etc.: Targets below iOS 18.x fail to launch app due to dyld[xxxxx]: Symbol not found: errors when referencing: MeshResource.init(from:) async - https://developer.apple.com/documentation/realitykit/meshresource/init(from:)-b7hb i.e. dyld[61511]: Symbol not found: _$s10RealityKit12MeshResourceC0A10FoundationE4fromACSayAD0C10DescriptorVG_tYaKcfC MeshResource.replace(with:) async - https://developer.apple.com/documentation/realitykit/meshresource/replace(with:)-8uvri i.e. dyld[78830]: Symbol not found: _$s10RealityKit12MeshResourceC0A10FoundationE7replace4withyAcDE8ContentsV_tYaKF Targets tested that exhibit issue: (DYLD errors) Device: iOS 17.7.2, iPhone 14 Pro Max Simulator: iOS 17.5 (21F79), iPhone 15 System Information: macOS Version 15.3 (Build 24D60) Xcode 16.2 (23507) (Build 16C5032a) MRE -- include this code in your app: (no need to invoke, just reference) static func addOrUpdateEntityModel_MRE(_ entity: ModelEntity) async { let descriptor = MeshDescriptor(name: "MyDescriptor") do { if let modelComponent = entity.model { // update existing ModelComponent if let model = try? MeshResource.Model(id: "MyModelId", descriptors: [descriptor]) { var contents = MeshResource.Contents() contents.models = .init([model]) try await modelComponent.mesh.replace(with: contents) /// `dyld[78830]: Symbol not found: _$s10RealityKit12MeshResourceC0A10FoundationE7replace4withyAcDE8ContentsV_tYaKF` } } else { //create new ModelComponent /// Comment-out the 2 lines below == dyld error for above `MeshResource.replace(with:)` let meshRes = try await MeshResource(from: [descriptor]) /// `dyld[61511]: Symbol not found: _$s10RealityKit12MeshResourceC0A10FoundationE4fromACSayAD0C10DescriptorVG_tYaKcfC` entity.model = .init(mesh: meshRes, materials: [SimpleMaterial()]) } } catch { fatalError() } }
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Feb ’25
Request for gaze data in fully immersive Metal apps
Hi, We are trying to port our Unity app from other XR devices to Vision Pro. Thus it's way easier for us to use the Metal rendering layer, fully immersive. And to stay true to the platform, we want to keep the gaze/pinch interaction system. But we just noticed that, unlike Polyspatial XR apps, VisionOS XR in Metal does not provide gaze info unless the user is actively pinching... Which forbids any attempt to give visual feedback on what they are looking at (buttons, etc). Is this planned in Apple's roadmap ? Thanks
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Feb ’25
Can I Use Xcode and iPadOS 18? (and RealityView)
I'm preparing my submission for the Swift Student Challenge, and I have a couple of questions regarding the development environment. Is it allowed to use Xcode to program my scene, or do I have to use Swift Playgrounds? Can I use iPadOS 18 for development? I noticed that Swift Playgrounds currently only supports up to iPadOS 17.5, but I would like to use RealityView, which is only available starting from iPadOS 18. I appreciate any clarification on this. Thanks in advance!
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Feb ’25
ARMeshAnchor Data with RealityView
I want to use SwiftUI and RealityView to get AR scene understanding data (ARMeshAnchor) on iOS devices with LiDAR. The only way we can do that is by using ARSession (unless there is another way). However in previous iOS 18 builds there was this function: https://developer.apple.com/documentation/realitykit/spatialtrackingsession/run(_:session:arconfiguration:) , which worked with SpatialTrackingSession and a custom ARSession together. This function in the the latest iOS and Xcode has since been removed in the RealityKit framework but still there on documentation. I also wanted to get ARFaceAnchor data which I still cannot get without ARSession, the closest I can get is by using: let target = AnchoringComponent.Target.face let anchoringComponent = AnchoringComponent(target, trackingMode: .predicted) entity = Entity() entity!.components.set(anchoringComponent) But I still can't find a way to get the current frame (ARFrame) or the anchors ([ARAnchor]) in the view. Alternatively if I use if I use this function: https://developer.apple.com/documentation/realitykit/spatialtrackingsession/run(_:) and start the ARSession separately. The session (didUpdate and didAdd) only runs for a few frames before getting interrupted. And if I completely remove SpatialTrackingConfiguration and just run the ARSession. There still is a valid tracked entity for the AnchoringComponent.Target.face component. IF in the configuration for the ARSession I use the ARWorldTrackingConfiguration with face tracking. And I still get updated facial data each frame. But the ARSession didUpdate or didAdd functions don't get called passed the first few frames. Interestingly if I switch the RealityViewCameraContent.RealityViewCamera to .virtual. I get ARMeshAnchor and ARFaceAnchor data, but no camera feed (as expected). This with or without SpatialTrackingConfiguration. My overarching question is what is the proper way to access ARMeshAnchors and other ARAnchors created by the system and track them live while also using SwiftUI. GitHub Repo with sample project can be found here: https://github.com/bpate75/RealityViewTesting
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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