Hello everyone, I must have missed something but why isn't there a depthAttachmentPixelFormat to the new Metal 4 MTL4RenderPipelineDescriptor, unlike the old MTLRenderPipelineDescriptor? So how do you set the depth pixel format? Thanks in advance!

Hi everyone, I'm building a native iOS app using Unreal Engine 5.6 with Firebase for authentication and Firestore. The app uses a MetaHuman avatar and is meant to run as a standalone UE app on iPhone. I'm using this Firebase wrapper: 👉 https://pandoa.github.io/FirebaseFeatures/ I've followed all the steps, including: Adding GoogleService-Info.plist to the Xcode project and ensuring it’s in the correct target Calling FIRApp.configure() in AppDelegate Verifying the plist is bundled correctly However, the app crashes on launch, and Firebase does not initialize properly. Crash log shows: [FirebaseCore][I-COR000005] No app has been configured yet. Setup details: Unreal Engine: 5.6 (source build, macOS) iOS Deployment: 17.5 MetaHuman character packaged correctly and app launches fine without Firebase Has anyone here managed to get Firebase working inside a native Unreal Engine iOS app with this setup? I'd love to hear if there’s something I’m missing — maybe something with initialization timing or module loading? Thanks so much in advance 🙏

I've had no issue calling image files in my .swift files, but they are causing crashes when used in my .SKS files. When I set a sprite texture to an image in the inspector/ editor bar, at runtime when that sprite is being called I get the error: "Cannot get value with size 16. The type encoded as {CGRect={CGPoint=dd}{CGSize=dd}} is expected to be 32 bytes." From my research it has something to do with Apple switching from 32 to 64 bite machines. From chatGPT “SpriteKit under the hood uses NSKeyedUnarchiver to load your .sks file. That unarchiver decodes each archived property by reading a fixed‑size blob of bytes and mapping it into a C struct. In your case it ran into a mismatch”. I am using a 64-bite machine to write my code and 64-bite simulators and physical devices, so there isn't a clear cause of the mismatch. My scenes play fine in Xcode 16's preview window and my code builds, it just crashes at runtime. When I don’t use image textured assets in the SKS file it works fine. It loads animated labels, and plain color squares. I’ve been able to work around this for static things like a sprite with a background texture by. in a normal non-game swift file, writing code like: if let scene = SKScene(fileNamed: "GameScene2") { let bg = SKSpriteNode(imageNamed: "YourBackgroundImage") bg.position = CGPoint(x: scene.frame.midX, y: scene.frame.midY) bg.zPosition = -1 scene.addChild(bg) } The issue now is I want to make a particle emitter and other non static sprites, but my understanding of their properities isn’t deep enough to create them without the editor. Also when I set SKTexture in a swift file that causes the same runtime crash with the 16/32 error. Could you help me figure out how to fix the bug so I can use the editor again? Otherwise could you help me figure out how to write a workaround like I do for background images? I have a feeling the answer is in writing my own NSKeyedUnarchiver but I don’t know how to make sure it’s called instead of the default one. I've already tried cleaning my code multiple times and deleting and reading sprite nodes. Thank you.

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.

Hello, I'm tracking down a bug where useResource doesn't seem to apply proper synchronization when a resource is produced by the render pass then consumed by the compute pass, but when I use MTLFence between the to signal and wait between the render/compute encoders, the artifact goes away. The resource is created with MTLHazardTrackingModeTracked and useResource is called on the compute encoder after the render pass. Metal API Validation doesn't report any warnings/errors. Am I misunderstanding the difference between the two APIs? I dug through the Metal documentation and it looks like useResource should handle synchronization given the resource has MTLHazardTrackingModeTracked but on the other hand, MTLFence should be used to ensure proper synchronization between command encoders. Can someone can clarify the difference between the two APIs and when to use them.

I'm having issues getting a well built package from the Apple Unity Plug-in project. When building the my game project in Unity the following error is printed to the console: Apple.Core.AppleNativeLibraryUtility] Cannot locate a Debug or Release Apple.Core native library for iOS. Please ensure that the build invocation (build.py, xcodebuild, or Xcode) compiled cleanly and that the build was configured to support Debug on iOS. As far as I can tell the build did compile cleanly, but I might be missing something. If anyone can see what I'm doing wrong or has any insight it would be greatly appreciated. Setup is the following: macOS Tahoe 26 Beta Xcode-beta Version 26.0 beta 3 (17A5276g) Unity Plug-in branch: 2025-beta1 Unity game project version: 2022.3.60f M1 Macbook Pro The built packages have been imported into the game project through the Unity Package Manager using the tarball option pointing to the built packages from the Unity Plug-in project. The Unity Plug-in project has been built using the build.py file with the following: python3 build.py -m iOS iPhoneSimulator -p Core GameKit CoreHaptics GameController -k all The output is available in the attached file. build-output.txt Here's an image of the NativeLibraries~ folder inside the built Apple.Core package.

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.

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.

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) }

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?

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)

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.

I am using Unreal Engine 5.6 on a MacBook Pro with an M3 chip and macOS 15.5. I’ve installed Xcode and accepted the license, but Unreal is not detecting the latest Metal Shader Standard (Metal v3.0). The maximum version Unreal sees is Metal v2.4, even though the hardware and OS should support Metal 3.0. I’ve also run sudo xcode-select -s /Applications/Xcode.app and accepted the license via Terminal. Is there anything in Xcode settings, SDK availability, or system permissions that could be preventing access to Metal 3.0 features?"

Hello experts, I have implemented 3d guassian splating rendering through the CompositorServices framework, but I want to port it to the RealityKit framework. I am not sure whether RealityKit meets the requirements. In order to port the code, I need to render a large number of instanced planes (it is necessary to support instantiated Mesh), and completely custom vertex shader and fragment shader code, including using instance_id and discarding pixels (Call the discard_fragment method). Some Metal code snippets: vertex ColorInOut splatVertexShader(uint vertexID [[vertex_id]], uint instanceID [[instance_id]], ushort amp_id [[amplification_id]], constant Splat* splatArray [[ buffer(BufferIndexSplat) ]], constant UniformsArray & uniformsArray [[ buffer(BufferIndexUniforms) ]], constant int32_t* splatIndices [[ buffer(BufferIndexSplatIndex) ]]) { // ... （do some calculations） } fragment half4 splatFragmentShader(ColorInOut in [[stage_in]]) { // ... if (/* a certain condition */) { discard_fragment(); } } I have learned that CustomMaterial does not support vision, and Shader Graph does not support custom vertex/fragment shader code. I also noticed the LowLevelMesh interface, but I didn't find any sample code with custom shader code, so it's not clear whether it would be able to achieve what I need. Can these requirements be met using reality?

Hi , My application meet below crash backtrace at very low repro rate from the public users, i do not see it relate to a specific iOS version or iPhone model. The last code line from my application is calling CAMetalLayer nextDrawable API. I did some basic studying, suppose it may relate to the wrong CAMetaLayer configuration, like frame property w or h <= 0.0 bounds property w or h <= 0.0 drawableSize w or h <= 0.0 or w or h > max value (like 16384) Not sure my above thinking is right or not? Will the UIView which my CAMetaLayer attached will cause such nextDrawable crash or not ? Thanks a lot Main Thread - Crashed libsystem_kernel.dylib __pthread_kill libsystem_c.dylib abort libsystem_c.dylib __assert_rtn Metal MTLReportFailure.cold.1 Metal MTLReportFailure Metal _MTLMessageContextEnd Metal -[MTLTextureDescriptorInternal validateWithDevice:] AGXMetalA13 0x245b1a000 + 4522096 QuartzCore allocate_drawable_texture(id<MTLDevice>, __IOSurface*, unsigned int, unsigned int, MTLPixelFormat, unsigned long long, CAMetalLayerRotation, bool, NSString*, unsigned long) QuartzCore get_unused_drawable(_CAMetalLayerPrivate*, CAMetalLayerRotation, bool, bool) QuartzCore CAMetalLayerPrivateNextDrawableLocked(CAMetalLayer*, CAMetalDrawable**, unsigned long*) QuartzCore -[CAMetalLayer nextDrawable] SpaceApp -[MetalRender renderFrame:] MetalRenderer.mm:167 SpaceApp -[FrameBuffer acceptFrame:] VideoRender.mm:173 QuartzCore CA::Display::DisplayLinkItem::dispatch_(CA::SignPost::Interval<(CA::SignPost::CAEventCode)835322056>&) QuartzCore CA::Display::DisplayLink::dispatch_items(unsigned long long, unsigned long long, unsigned long long) QuartzCore CA::Display::DisplayLink::dispatch_deferred_display_links(unsigned int) UIKitCore _UIUpdateSequenceRun UIKitCore schedulerStepScheduledMainSection UIKitCore runloopSourceCallback CoreFoundation __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ CoreFoundation __CFRunLoopDoSource0 CoreFoundation __CFRunLoopDoSources0 CoreFoundation __CFRunLoopRun CoreFoundation CFRunLoopRunSpecific GraphicsServices GSEventRunModal UIKitCore -[UIApplication _run] UIKitCore UIApplicationMain

When I take a frame capture of my application in Xcode, it shows a warning that reads "Your application created separate command encoders which can be combined into a single encoder. By combining these encoders you may reduce your application's load/store bandwidth usage." In the minimal reproduction case I've identified for this warning, I have two render pipeline states: The first writes to the current drawable, the depth buffer, and a secondary color buffer. The second writes only to the current drawable. Because these are writing to a different set of outputs, I was initially creating two separate render command encoders to handle the draws under each of these states. My understanding is that Xcode is telling me I could only create one, however when I try to do that, I get runtime asserts when attempting to apply the second render pipeline state since it doesn't have a matching attachment configured for the second color buffer or for the depth buffer, so I can't just combine the encoders. Is the only solution here to detect and propagate forward the color/depth attachments from the first state into the creation of the second state? Is there any way to suppress this specific warning in Xcode?

Apple, please bring back SceneKit.

Hello I would like to know how to combine 2 animations with RealityKit (one animation for the arms and one for the legs for example) I saw this apple demo that seems to explain it but I don't understand at all how to do it... Thanks

The sample code here, has code like: // Create a display link capable of being used with all active displays cvReturn = CVDisplayLinkCreateWithActiveCGDisplays(&_displayLink); But that function's doc says it's deprecated and to use NSView/NSWindow/NSScreen displayLink instead. That returns CADisplayLink, not CVDisplayLink. Also the documentation for that displayLink method is completely empty. I'm not sure if I'm supposed to add it to run loop, or what, after I get it. It would be nice to get an updated version of this sample project and/or have some documentation in NSView.displayLink

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?