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)
Delve into the world of graphics and game development. Discuss creating stunning visuals, optimizing game mechanics, and share resources for game developers.
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I am integrating MetalFX FrameInterpolator into a custom Unity RenderGraph–based render pipeline (C++ native plugin + C# render passes), and I am hitting the following assertion at runtime:
/MetalFXDebugError.h:29: failed assertion `Color texture width mismatch from descriptor'
What makes this confusing is that all input/output textures have the correct width and height, and they exactly match the values specified in the MTLFXFrameInterpolatorDescriptor.
Setup
Input resolution: 1024 x 512
Output resolution: 2048 x 1024
MTLFXTemporalScaler is created first and then passed into MTLFXFrameInterpolator
The TemporalScaler and FrameInterpolator descriptors use the same input/output sizes and formats
All Metal textures:
Have no parentTexture
Are 2D textures
Match the descriptor sizes exactly (verified via logging)
Texture bindings at encode time
frameInterpolator.colorTexture = mtlTexColor; // 1024 x 512
frameInterpolator.prevColorTexture = mtlTexPrevColor; // 1024 x 512
frameInterpolator.motionTexture = mtlTexMotion; // 1024 x 512
frameInterpolator.depthTexture = mtlTexDepth; // 1024 x 512
frameInterpolator.uiTexture = mtlTexUI; // 2048 x 1024
frameInterpolator.outputTexture = mtlTexOutput; // 2048 x 1024
All widths/heights are logged and match:
Color : 1024 x 512 (input)
PrevColor : 1024 x 512 (input)
Motion : 1024 x 512 (input)
Depth : 1024 x 512 (input)
UI : 2048 x 1024 (output)
Output : 2048 x 1024 (output)
The TemporalScaler works correctly on its own.
The assertion only occurs when using FrameInterpolator.
Important detail about colorTexture
Originally, colorTexture was copied from BuiltinRenderTextureType.CurrentActive.
After reading that this might violate MetalFX semantics, I changed the pipeline so that:
colorTexture now comes from a dedicated private RenderGraph texture
It is not the backbuffer
It is not a drawable
It is not used as a final output
It is created before UI rendering
Despite this, the assertion still occurs.
Question
Can uiTexture for MTLFXFrameInterpolator legally come from a texture copied from BuiltinRenderTextureType.CurrentActive?
More generally:
Are there additional hidden constraints on colorTexture / prevColorTexture (such as Metal usage, storageMode, aliasing, or hazard tracking) that could cause this assertion, even when sizes match?
Does FrameInterpolator require colorTexture and prevColorTexture to be created in a very specific way (e.g. non-aliased, ShaderRead usage, identical Metal resource properties)?
Any clarification on the exact semantic requirements for colorTexture, prevColorTexture, or uiTexture in MetalFX FrameInterpolator would be greatly appreciated.
Hello,
I've been trying to leverage instanced rendering in RealityKit on visionOS but have not had success.
RealityKit states this is supported:
https://developer.apple.com/documentation/realitykit/validating-usd-files
https://developer.apple.com/videos/play/wwdc2021/10075/?time=1373
https://developer.apple.com/videos/play/wwdc2023/10099/?time=772
RealityKit Trace metrics
Validating instancing is working:
To test I made a base visionOS app with immersive space and the entity replaced with my test usdz file. I've been using the RealityKit Trace profiling template in xcode instruments in the immersive space and volume closed. This gets consistent draw call results.
If I have a single sphere mesh with one material I get one draw call, but the number of draw calls grows linearly with mesh count no matter how my entity is configured.
What I've tried
Create a test scene in blender, export with instancing enabled
Create a test scene in Reality Composer Pro using references
Author usda files by hand based on the OpenUSD spec
Programatically create a MeshResource with Contents at runtime
References
https://openusd.org/release/api/_usd__page__scenegraph_instancing.html
https://developer.apple.com/documentation/realitykit/meshresource
https://developer.apple.com/documentation/realitykit/meshresource/instance
Thank you
Can I use them in SK and do the animations work?
Thanks, Patrick
After updating to MacOS 26.1 I encountered an issue that Roblox tends to freeze quite often for 10 - 60 seconds at most, this is really annoying that it is doing this as i play the game a lot. My theory is that it is like a driver issue with metal or something, I have reinstalled MacOS, reinstalled the game and lowed the performance manually but nothing is working.
Wondering if you could help, when it will be fixed and if others are having the same issue.
Many thanks, William.
I'm developing a turn based game. When I present the GKTurnBasedMatchmakerViewController players can opt in for automatch instead of selecting a specific friend as opponent.
How exactly does the matching work if a player doesn't specify anything explicitly?
Does Game Center send push notifications in a round robin fashion to all friends and the first one to accept is then matched as opponent? Is this documented somewhere?
I can't create any breakpoint in my Xcode after I upgraded to macOS 15.4
macOS: Version 15.4 (24E248)
visionOS Simulator: 2.3
Xcode: Version 16.2 (16C5032a)
My app works well without any breakpoints.
But if I create any breakpoint it shows me this:
Couldn't find the Objective-C runtime library in loaded images.
Message from debugger: The LLDB RPC server has crashed. You may need to manually terminate your process. The crash log is located in ~/Library/Logs/DiagnosticReports and has a prefix 'lldb-rpc-server'. Please file a bug and attach the most recent crash log.
I haven't been looking at screensavers for a long time because of Apple's lack of will (or resources?) to provide a public version of the private modern SDK used by Apple for a very long time now.
I'm now looking at the Screen Saver pane in System Settings (the What-If version of System Preferences in an alternate universe where all screens are in portrait mode).
In macOS Sequoia, it seems like 3rd party screensavers are not welcome considering that they are relegated to the "Other" section at the bottom of the list and you have to click Show All to start seeing 3rd party screen savers.
I also had a quick look at macOS Tahoe Beta 3 and it looks like that all the real screensavers are gone (3rd party and the ones from Apple: Hello, Message, Flurry, etc.) or at least it requires to be a Nobel Prize to find them (and the Search field is not useful).
I tried to install a 3rd party screen saver on macOS Tahoe Beta 3, it doesn't show up in the list.
To summarize:
No public access to modern APIs AFAIK.
UI that is hostile to 3rd party screen savers on macOS Sequoia.
Apparently only screensavers that are slideshows or movies curated by Apple in macOS Tahoe b3.
Hence the question:
Is there any future for screen savers on macOS?
Because if there's none, I won't waste my time trying to update some old screen savers.
Recently, I adopted MetalFX for Upscale feature.
However, I have encountered a persistent build failure for the iOS Simulator with the error message, 'MetalFX is not available when building for iOS Simulator.'
To address this, I modified the MetalFX.framework status to 'Optional' within Build Phases > Link Binary With Libraries, adding the linker option (-weak_framework). Despite this adjustment, the build process continues to fail.
Furthermore, I observed that the MetalFX sample application provided by Apple, specifically the one found at https://developer.apple.com/documentation/metalfx/applying-temporal-antialiasing-and-upscaling-using-metalfx, also fails to build for the iOS Simulator target.
Has anyone encountered this issue?
Hi Apple team,
Game Mode was introduced in iOS 18. To activate Game Mode, an app must include specific key-value pairs in its *.plist and be categorized as a "Game" on the App Store.
My app (https://apps.apple.com/us/app/voidlink/id6747717070) works primarily as a self-hosted game streaming (PC->iPhone/iPad) client. Game Mode provides clear benefits in terms of latency and frame rate stability, but it can currently only be activated when running via Xcode or TestFlight.
I am an individual iOS developer based in China, where an additional government license is required for apps to be listed under the "Game" category on the App Store. Obtaining such a license is very difficult for independent developers, so my app has been categorized under "Utilities" instead.(If move the app to game category, it will disappear from Chinese App Store immediately)
Expectation / Suggestion:
Please consider making Game Mode available as a local, user-controllable option on iOS18/26+, such as through a system “App Pool” where users can choose which apps to enable Game Mode for, regardless of App Store category.
This would greatly benefit use cases like streaming clients, benchmarking tools, and remote play utilities, without requiring developers to reclassify their apps as “Games” on App Store.
Topic:
Graphics & Games
SubTopic:
General
I work on a Qt/QML app that uses Esri Maps SDK for Qt and that is deployed to both Windows and iPads. With a recent iPad OS upgrade to 26.1, many iPad users are reporting the application freezing after panning and/or identifying features in the map. It runs fine for our Windows users.
I was able to reproduce this and grabbed the following error messages when the freeze happens:
IOGPUMetalError: Caused GPU Address Fault Error (0000000b:kIOGPUCommandBufferCallbackErrorPageFault)
IOGPUMetalError: Invalid Resource (00000009:kIOGPUCommandBufferCallbackErrorInvalidResource)
Environment:
Qt 6.5.4 (Qt for iOS)
Esri Maps SDK for Qt 200.3
iPadOS 26.1
Because it appears to be a Metal error, I tried using OpenGL (Qt offers a way to easily set hte target graphics api):
QQuickWindow::setGraphicsApi(QSGRendererInterface::GraphicsApi::OpenGL)
Which worked! No more freezing. But I'm seeing many posts that OpenGL has been deprecated by Apple.
I've seen posts that Apple deprecated OpenGL ES. But it seems to still be available with iPadOS 26.1. If so, will this fix (above) just cause problems with a future iPadOS update?
Any other suggestions to address this issue? Upgrading our version of Qt + Esri SDK to the latest version is not an option for us. We are in the process to upgrade the full application, but it is a year or two out. So, we just need a fix to buy us some time for now.
Appreciate any thoughts/insights....
I am rewriting an unfinished SceneKit project as RealityKit (NonAR). As far as I can see, RealityKit is missing basic fog functionality?
Fog was simple & easy to implement in SCeneKit (fogStartDistance / fogEndDistance / fogDensityExponent / fogColor). Are there any plans to implement something like this in RealityKit?
Are there any simple workarounds?
Topic:
Graphics & Games
SubTopic:
RealityKit
Developing a prototype Vision Pro app and would like to render a 3D scene made from Reality Composer Pro on an image anchor in a RealityView. But I have no luck so far to make it work and need some guidance to move on.
I got the image file stored in the assets like below:
And from below is the source codes:
import SwiftUI
import RealityKit
import RealityKitContent
struct AnchorView: View {
@State var imageEntity: Entity = {
let anchorEntity = AnchorEntity(.image(group: "AR Resources", name: "reanchor"))
return anchorEntity
}()
var body: some View {
RealityView { content in
do
{
// Add the initial RealityKit content
if let scene = try? await Entity(named: "Scene", in: realityKitContentBundle)
{
imageEntity.addChild(scene)
content.add(imageEntity)
}
}
catch
{
print("Error occurs when adding reality view content: \(error)")
}
}
}
}
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)
}
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.
A bit of background on what our app is doing:
We have a RealityKit ARView session running.
During this period we place objects in RealityKit.
At some point user can "take photo" and we use session.captureHighResolutionFrame to capture a frame.
We then use captured frame and frame.camera.projectPoint to project my objects back to 2D
Issue we found is that on devices that have iOS26, first photo user takes and the first frame received from session.captureHighResolutionFrame gives incorrect CGPoint for frame.camera.projectPoint. If user takes the second photo with the same camera phostion, second frame received from session.captureHighResolutionFrame gives correct CGPoint for frame.camera.projectPoint
I notices some difference between first and subsequent frames that i believe is corresponding with the issue. Yaw value of camera (frame.camera.eulerAngles.y) on first frame is not correct ( inconsistent with any subsequent frame)
I also created a small example app and i followed Building an Immersive Experience with RealityKit example to create it. The issue exists in this app for iOS26, while iOS18.* has consistent values between first and subsequent captured frames.
Note:
The yaw value seems to differ more if we start session in portrait but take photo in landscape.
Example result for 3 captured frames:
Frame captured with yaw: 1.4855177402496338
Frame captured with yaw: -0.08803760260343552
Frame captured with yaw: -0.08179682493209839
Example code:
class CustomARView: ARView, ARSessionDelegate {
required init(frame: CGRect) { super.init(frame: frame) }
required init?(coder decoder: NSCoder) { fatalError("init(coder:) has not been implemented")}
func setup() {
let singleTap = UITapGestureRecognizer(target: self, action: #selector(handleTap))
addGestureRecognizer(singleTap)
}
@objc
func handleTap(_ gestureRecognizer: UIGestureRecognizer) {
Task {
do {
let frame = try await session.captureHighResolutionFrame()
print("Frame captured with yaw: \(Double(frame.camera.eulerAngles.y))")
} catch { }
}
}
}
struct CustomARViewUIViewRepresentable: UIViewRepresentable {
func makeUIView(context: Context) -> some UIView {
let arView = CustomARView(frame: .zero)
arView.setup()
return arView
}
func updateUIView(_ uiView: UIViewType, context: Context) { }
}
struct ContentView: View {
var body: some View {
CustomARViewUIViewRepresentable()
.frame(maxWidth: .infinity, maxHeight: .infinity)
.ignoresSafeArea()
}
}
During editing in Pages (or Word) I am getting these glitches (see attachment).
Started after the last update to Mac OS 26.3 (beta)
Also removed 2 recent instalments (Blackhole audio driver and kDrive/Infomaniak, but trouble is still there.
27" iMac 2020 (Intel)
i7 3,8 Ghz
AMD Radeon Pro 5500 XT 8 GB
24 GB RAM
macOS Tahoe 26.3 (=beta)
Tried restart in safe mode, checked fonts. Talked to aissistent to get a solution, but no ...)
Thx for any advice, Pieter (not a developer so please kee pit simple 🙏🏻)
If I create a bitmap image and then try to get ready to draw into it, like so:
NSBitmapImageRep* newRep = [[NSBitmapImageRep alloc]
initWithBitmapDataPlanes: nullptr
pixelsWide: 128
pixelsHigh: 128
bitsPerSample: 8
samplesPerPixel: 4
hasAlpha: YES
isPlanar: NO
colorSpaceName: NSDeviceRGBColorSpace
bitmapFormat: NSBitmapFormatAlphaNonpremultiplied |
NSBitmapFormatThirtyTwoBitBigEndian
bytesPerRow: 4 * 128
bitsPerPixel: 32];
[NSGraphicsContext setCurrentContext:
[NSGraphicsContext graphicsContextWithBitmapImageRep: newRep]];
then the log shows this error:
CGBitmapContextCreate: unsupported parameter combination:
RGB
8 bits/component, integer
512 bytes/row
kCGImageAlphaLast
kCGImageByteOrderDefault
kCGImagePixelFormatPacked
Valid parameters for RGB color space model are:
16 bits per pixel, 5 bits per component, kCGImageAlphaNoneSkipFirst
32 bits per pixel, 8 bits per component, kCGImageAlphaNoneSkipFirst
32 bits per pixel, 8 bits per component, kCGImageAlphaNoneSkipLast
32 bits per pixel, 8 bits per component, kCGImageAlphaPremultipliedFirst
32 bits per pixel, 8 bits per component, kCGImageAlphaPremultipliedLast
32 bits per pixel, 10 bits per component, kCGImageAlphaNone|kCGImagePixelFormatRGBCIF10|kCGImageByteOrder16Little
64 bits per pixel, 16 bits per component, kCGImageAlphaPremultipliedLast
64 bits per pixel, 16 bits per component, kCGImageAlphaNoneSkipLast
64 bits per pixel, 16 bits per component, kCGImageAlphaPremultipliedLast|kCGBitmapFloatComponents|kCGImageByteOrder16Little
64 bits per pixel, 16 bits per component, kCGImageAlphaNoneSkipLast|kCGBitmapFloatComponents|kCGImageByteOrder16Little
128 bits per pixel, 32 bits per component, kCGImageAlphaPremultipliedLast|kCGBitmapFloatComponents
128 bits per pixel, 32 bits per component, kCGImageAlphaNoneSkipLast|kCGBitmapFloatComponents
See Quartz 2D Programming Guide (available online) for more information.
If I don't use NSBitmapFormatAlphaNonpremultiplied as part of the format, I don't get the error message. My question is, why does the constant NSBitmapFormatAlphaNonpremultiplied exist if you can't use it like this?
If you're wondering why I wanted to do this: I want to extract the RGBA pixel data from an image, which might have non-premultiplied alpha. And elsewhere online, I saw advice that if you want to look at the pixels of an image, draw it into a bitmap whose format you know and look at those pixels. And I don't want the process of drawing to premultiply my alpha.
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.
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?
Topic:
Graphics & Games
SubTopic:
RealityKit