Hi, I am working with a large project. We are compiling each material to its own .metallib. They all include many common files full of inline functions. Finally we link it all together at the end with a single big pathtrace kernel. Everything works as expected, however the compile times have gotten completely out of hand and it takes multiple minutes to compile at runtime (to native code). I have gathered that I can do this offline by using metal-tt however if I am wondering if there is a way to reduce the compile times in such a scenario, and how to investigate what the root cause of the problem is. I suspect it could have to do with the fact that every materials metallib contains duplications of all the inline functions. Any ideas on how to profile and debug this? Thanks, Rasmus

Hi all, I've encountered a potential issue with how the winding order of geometry is handled when their transformations involve negative scaling. I created a simple test asset, a single triangle, to demonstrate this. The triangle's vertices are defined in a counter-clockwise ("right-handed") winding order, and its transform has a negative scale on the X-axis. According to the OpenUSD specification, this negative determinant in the transformation matrix should effectively reverse the winding order of the geometry: However, any given gprim's local-to-world transformation can flip its effective orientation, when it contains an odd number of negative scales. This condition can be reliably detected using the (Jacobian) determinant of the local-to-world transform: if the determinant is less than zero, then the gprim's orientation has been flipped, and therefore one must apply the opposite handedness rule when computing its surface normals (or just flip the computed normals) for the purposes of hidden surface detection and lighting calculations. When I view the asset in tools like Blender or Preview on macOS, it behaves as expected. The triangle's effective orientation is flipped to CW. However, when the same asset is viewed in Reality Composer Pro or with QuickLook on iOS, its effective orientation remains CCW. In other words, the triangle faces the opposite direction. My questions for the community and Apple are: Is this behavior in RealityKit a known issue? If this is a known issue, is there official guidance for DCC tools on how to export USDZ assets to ensure they appear correctly in the Apple ecosystem? Any insights or recommendations would be greatly appreciated.

Hi, I'm Beginner with Metal 4 and Model I/O 🥺. I can render simple models with just one mesh, but when I try to render models with SubMeshes, nothing shows up on screen. Can anyone help me figure out how to properly render models with multiple submeshes? I think I'm not iterating through them correctly or maybe missing some buffers setup. Here's what I have so far: https://www.icloud.com.cn/iclouddrive/0a6x_NLwlWy-herPocExZ8g3Q#LoadModel

We have a released game in the App Store with Game Center Challenges. The challenges were working well in testing of the final version before the Game Center challenges went live. After release the activity that should take the player to the challenge in game results in this printout and we do not get informed by GKGameActivityListener of the activity happening in our code as we did before the Game Center challenges went live. “Invalid game activity definition. Failed to kick activity notification to GameKit. Error: Error Domain=GKErrorDomain Code=17 "(null)"” Also, Game Center reports that the are no challenges in GKChallengeDefinition.all even though there are ongoing challenges. The leaderboard results do get reported to Game Center though and show up as challenge entries in the Games app. At the moment we are trying to figure out if this is a problem on our end or a Game Center server issue.

Added achievements to my approved app. Added them for the next release version, which I am running in simulator. When I look at the Achievements page, I can see that there are 17 Achievements available (correct), but they all show as hidden, despite checking the "No" box in App Store Connect.

Hi, Since iOS 26 introduced the new Games app, I’ve noticed a problem when using a Nintendo Switch Pro Controller in wired USB-C mode, and also with third-party controllers that emulate it (like the GameSir X5 Lite). In the Games app interface, only the L/R buttons respond, but the D-Pad and analog sticks don’t work at all. Once inside actual games, the controller works fine — the issue only affects the Games app UI. What I’ve tested so far: Xbox / PlayStation controllers → work fine in both wired and Bluetooth, including inside the Games app. Switch Pro Controller (Bluetooth) → works fine, including in the Games app. Switch Pro Controller (wired) → same issue as the X5 Lite, D-Pad and sticks don’t work in the Games app. This makes it hard to use the new Games app launcher with these controllers, even though they work perfectly once a game is launched. My question: is this an iOS bug (Apple needs to add proper support for wired Switch Pro controllers in the Games app), or something that Nintendo / GameSir would need to address? Thanks in advance to anyone who can confirm this or provide more info.

I'm trying to convert my game from SceneKit to RealityKit. I noticed that even when the scene is static (nothing moves), RealityKit keeps using CPU. In SceneKit, CPU goes down to 0% with a static scene. With this simplest of games, RealityKit keeps using about 65% CPU: class ViewController: NSViewController { override func loadView() { view = ARView(frame: NSScreen.main!.frame) } } Is this expected or a bug? I created FB22125047.

Just wondering if anyone knows what it will take to hit greater than 60hz when targeting iPhone. If I set the preferredFramesPerSecond of an MTKView to 120, it works on the iPad, but on iPhone it never goes over 60hz, even with a simple hello triangle sample app... is this a limitation of targeting iPhone?

I'm trying to use MTLBinaryArchive. I collected a BinaryArchive from one device and used metal-tt to translate it for all supported iPhone devices, ranging from iPhone 7 Plus to iPhone 16. However, this BinaryArchive is quite large, around 1.5GB uncompressed, and about 500MB compressed in the IPA. I'm wondering how to address the size issue. I watched the WWDC 2022 video, which mentioned that the operating system or app installation process would handle compatibility. Does this compatibility support different GPU chips? I tried installing an IPA with a BinaryArchive collected only from an iPhone 12 on an iPhone 13, but the BinaryArchive didn't take effect. I also saw that Apple supports App Thinning. However, it seems that resources in the Asset Catalog cannot be accessed via URL, and creating an MTLBinaryArchive requires a URL. Is it possible for MTLBinaryArchive to be distributed through App Thinning? The WWDC 2022 video also mentioned using the -Os optimization flag to reduce size. Can this give an estimate of how much compression it would achieve? Are there any methods to solve the BinaryArchive size issue without impacting performance?

Hello - Upon enabling debug mode for GameKit configuration for my iOS app, I do not see any devices (my iPhone or simulators) in the device list within the "Manage Game Progress" debug tool. I only see my Mac as a device. Is there any trick to this or a way to add devices to this list? Thank you

Hi all, I'm encountering an issue with Metal raytracing on my M5 MacBook Pro regarding Instance Acceleration Structure (IAS). Intersection tests suddenly stop working after a certain point in the sampling loop. Situation I implemented an offline GPU path tracer that runs the same kernel multiple times per pixel (sampleCount) using metal::raytracing. Intersection tests are performed using an IAS. Since this is an offline path tracer, geometries inside the IAS never changes across samples (no transforms or updates). As sampleCount increases, there comes a point where the number of intersections drops to zero, and remains zero for all subsequent samples. Here's a code sketch: let sampleCount: UInt16 = 1024 for sampleIndex: UInt16 in 0..<sampleCount { // ... do { let commandBuffer = commandQueue.makeCommandBuffer() // Dispatch the intersection kernel. await commandBuffer.completed() } do { let commandBuffer = commandQueue.makeCommandBuffer() // Use the intersection test results from the previous command buffer. await commandBuffer.completed() } // ... } kernel void intersectAlongRay( const metal::uint32_t threadIndex [[thread_position_in_grid]], // ... const metal::raytracing::instance_acceleration_structure accelerationStructure [[buffer(2)]], // ... ) { // ... const auto result = intersector.intersect(ray, accelerationStructure); switch (result.type) { case metal::raytracing::intersection_type::triangle: { // Write intersection result to device buffers. break; } default: break; } Observations Encoding both the intersection kernel and the subsequent result usage in the same command buffer does not resolve the problem. Switching from IAS to Primitive Acceleration Structure (PAS) fixes the problem. Rebuilding the IAS for each sample also resolves the issue. Intersections produce inconsistent results even though the IAS and rays are identical — Image 1 shows a hit, while Image 2 shows a miss. Questions Am I misusing IAS in some way ? Could this be a Metal bug ? Any guidance or confirmation would be greatly appreciated.

Reproduce Same SIM card with 4G, same testing location, connected to the same server, xcode debugging game applications, network/profile retrotransmitted, Avg round trip to view data iPhone17， Turn off 4G and turn on WiFi. All the above indicators are acceptable iPhone17， Turn on 4G, turn off WiFi, retry with retransmission and very high Avg round trip iPhone14-16， Turn on 4G and turn off WiFi. All the above indicators are acceptable App Unity3d project .netframe4.0 C# Socket Other Many developers in Chinese forums have provided feedback on this issue

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.

I have tried every combination of suggestions to get a skybox to appear. Using swiftUI, realityKit and iOS. Non immersive environment. Does anyone have code that works to display a skybox. When i use a do/catch loop i get environmentResource not found. I have checked the syntax, ensured the folder is referencing the target, used the same name for the folder as the file, the file is a .hdr (i assume this is supported), i have moved the file folder to the top level - no change.

Hi everyone I'm experiencing an issue with iPadOS 26 regarding multi-touch gesture detection. When performing a quick four-finger gesture (tap and swipe), the system often fails to recognize the input. This especially affects multi-touch gestures, such as rhythm games with difficult levels. Steps to Reproduce: Place four fingers on the screen. Perform a quick tap or a quick horizontal swipe (like the one used to switch apps). Observe whether the gesture is ignored or detected inconsistently. Expected Behavior: 4-finger multitouch gestures should be recognized regardless of gesture speed, just like previous iPadOS versions. Actual Behavior: Gestures fail to be detected when executed quickly—same gestures still work, and miss notes in rhythm games. You can check out my posts on Twitter/x and Facebook: [https://x.com/kokona_fwa/status/1978131164104728949?s=61] Facebook: [https://m.facebook.com/groups/idipad/permalink/24438964899058806/?]

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!

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?

Hi, I'm trying to set the displayScale environment value for a RealityView, so it renders at 2x instead of 3x on the iPhone, but it seems to have no effect. .environment(\.displayScale, 2.0) Is this expected behavior, or a bug? The reason I want it to render at 2x and not at the default 3x is for game optimization and performance.

subj And how in this case are beautiful system dials made with smoke effects and other particles?

Is it possible to start screen recording (through Control Center) without user prompt? I mean to ask user permission for the first time and after that to start and stop recording programmatically only? I need to record screen only for specific events.