Hi,
How to enable multitouch on ARView?
Touch functions (touchesBegan, touchesMoved, ...) seem to only handle one touch at a time. In order to handle multiple touches at a time with ARView, I have to either:
Use SwiftUI .simultaneousGesture on top of an ARView representable
Position a UIView on top of ARView to capture touches and do hit testing by passing a reference to ARView
Expected behavior:
ARView should capture all touches via touchesBegan/Moved/Ended/Cancelled.
Here is what I tried, on iOS 26.1 and macOS 26.1:
ARView Multitouch
The setup below is a minimal ARView presented by SwiftUI, with touch events handled inside ARView. Multitouch doesn't work with this setup.
Note that multitouch wouldn't work either if the ARView is presented with a UIViewController instead of SwiftUI.
import RealityKit
import SwiftUI
struct ARViewMultiTouchView: View {
var body: some View {
ZStack {
ARViewMultiTouchRepresentable()
.ignoresSafeArea()
}
}
}
#Preview {
ARViewMultiTouchView()
}
// MARK: Representable ARView
struct ARViewMultiTouchRepresentable: UIViewRepresentable {
func makeUIView(context: Context) -> ARView {
let arView = ARViewMultiTouch(frame: .zero)
let anchor = AnchorEntity()
arView.scene.addAnchor(anchor)
let boxWidth: Float = 0.4
let boxMaterial = SimpleMaterial(color: .red, isMetallic: false)
let box = ModelEntity(mesh: .generateBox(size: boxWidth), materials: [boxMaterial])
box.name = "Box"
box.components.set(CollisionComponent(shapes: [.generateBox(width: boxWidth, height: boxWidth, depth: boxWidth)]))
anchor.addChild(box)
return arView
}
func updateUIView(_ uiView: ARView, context: Context) { }
}
// MARK: ARView
class ARViewMultiTouch: ARView {
required init(frame: CGRect) {
super.init(frame: frame)
/// Enable multi-touch
isMultipleTouchEnabled = true
cameraMode = .nonAR
automaticallyConfigureSession = false
environment.background = .color(.gray)
/// Disable gesture recognizers to not conflict with touch events
/// But it doesn't fix the issue
gestureRecognizers?.forEach { $0.isEnabled = false }
}
required dynamic init?(coder decoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
for touch in touches {
/// # Problem
/// This should print for every new touch, up to 5 simultaneously on an iPhone (multi-touch)
/// But it only fires for one touch at a time (single-touch)
print("Touch began at: \(touch.location(in: self))")
}
}
}
Multitouch with an Overlay
This setup works, but it doesn't seem right. There must be a solution to make ARView handle multi touch directly, right?
import SwiftUI
import RealityKit
struct MultiTouchOverlayView: View {
var body: some View {
ZStack {
MultiTouchOverlayRepresentable()
.ignoresSafeArea()
Text("Multi touch with overlay view")
.font(.system(size: 24, weight: .medium))
.foregroundStyle(.white)
.offset(CGSize(width: 0, height: -150))
}
}
}
#Preview {
MultiTouchOverlayView()
}
// MARK: Representable Container
struct MultiTouchOverlayRepresentable: UIViewRepresentable {
func makeUIView(context: Context) -> UIView {
/// The view that SwiftUI will present
let container = UIView()
/// ARView
let arView = ARView(frame: container.bounds)
arView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
arView.cameraMode = .nonAR
arView.automaticallyConfigureSession = false
arView.environment.background = .color(.gray)
let anchor = AnchorEntity()
arView.scene.addAnchor(anchor)
let boxWidth: Float = 0.4
let boxMaterial = SimpleMaterial(color: .red, isMetallic: false)
let box = ModelEntity(mesh: .generateBox(size: boxWidth), materials: [boxMaterial])
box.name = "Box"
box.components.set(CollisionComponent(shapes: [.generateBox(width: boxWidth, height: boxWidth, depth: boxWidth)]))
anchor.addChild(box)
/// The view that will capture touches
let touchOverlay = TouchOverlayView(frame: container.bounds)
touchOverlay.autoresizingMask = [.flexibleWidth, .flexibleHeight]
touchOverlay.backgroundColor = .clear
/// Pass an arView reference to the overlay for hit testing
touchOverlay.arView = arView
/// Add views to the container.
/// ARView goes in first, at the bottom.
container.addSubview(arView)
/// TouchOverlay goes in last, on top.
container.addSubview(touchOverlay)
return container
}
func updateUIView(_ uiView: UIView, context: Context) {
}
}
// MARK: Touch Overlay View
/// A UIView to handle multi-touch on top of ARView
class TouchOverlayView: UIView {
weak var arView: ARView?
override init(frame: CGRect) {
super.init(frame: frame)
isMultipleTouchEnabled = true
isUserInteractionEnabled = true
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let totalTouches = event?.allTouches?.count ?? touches.count
print("--- Touches Began --- (New: \(touches.count), Total: \(totalTouches))")
for touch in touches {
let location = touch.location(in: self)
/// Hit testing.
/// ARView and Touch View must be of the same size
if let arView = arView {
let entity = arView.entity(at: location)
if let entity = entity {
print("Touched entity: \(entity.name)")
} else {
print("Touched: none")
}
}
}
}
override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
let totalTouches = event?.allTouches?.count ?? touches.count
print("--- Touches Cancelled --- (Cancelled: \(touches.count), Total: \(totalTouches))")
}
}
RealityKit
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Activity
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)
Hi,
I can't see RealityKit statistics on Xcode Canvas using:
arView.debugOptions = [.showStatistics]
The statistics only show on a physical device, not Xcode live canvas with #Preview. Testing in Xcode 26.0.1 (17A400) on Tahoe 26.0.1 (25A362).
Use case: I'm using RealityKit as a non-AR 3D engine. Xcode Canvas is useful for live iterations.
Is this expected behavior? How can I see FPS on Xcode canvas? SKView for example shows all debug options on both Xcode Canvas and physical devices.
Topic:
Graphics & Games
SubTopic:
RealityKit
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
I have a question I guess more for the Apple team.
But why are there no totally 3D experiences for the Vision Pro lineup?
I know they have given us tools to implement unity 3D games into iPhone and I guess you can also build it in RealityKit. But why at this moment are 3D games limited to just iPad and iPhone and can't you bring that into Vision Pro?
Just to explain. When I say a totally 3D game, I mean games like Gorn. I mean the Vision Pro is definitely powerful enough, but it just feels limited to tabletop games and AR games.
Is this something Apple is thinking about implementing?
Topic:
Graphics & Games
SubTopic:
RealityKit
Tags:
ARKit
Reality Composer
RealityKit
Reality Composer Pro
What is the current [most recent] best practice to instancing Meshes in RealityKit?
I see both MeshInstanceComponent and MeshInstanceCollection.
My intent is to bind a transform to a Circle Agent (GameplayKit Agent), and feed that result to Instancing.
I'm working on an application for viewing AMF models on macOS, using RealityKit. AMF supports several different ways to color models, including per-vertex color (where the color of a triangle is interpolated from vertex to vertex) as well as per-face color (where the color of the triangle is the same across the entire face).
I'm trying to figure out how to support those color models using a RealityKit mesh. Apple's documentation (https://developer.apple.com/documentation/realitykit/modifying-realitykit-rendering-using-custom-materials) talks about per-vertex colors, but I haven't found a way to create a mesh that includes per-vertex colors, other than use a texture map (which might be the correct solution).
Can someone give me some pointers?
Hi!
Using ARView in UIKit or through a UIViewRepresentable in SwiftUI, we can do:
arView.debugOptions = [.showPhysics, .showStatistics]
What is the equivalent in RealityView?
Topic:
Graphics & Games
SubTopic:
RealityKit
Hey there, I’m currently planning to use RealityKit in a new multiplatform app I’m building. Unfortunately, I noticed that WatchOS is not supported for RealityKit, while SceneKit is getting deprecated. However, I’d like to maintain the same codebase across platforms. What are my options?
Hi team, I'm looking for the RealityKit debugger in Xcode 26 beta 3. I'm running a RealityKit app on my iPad running iPadOS 26 b3, but the debugger option is not there in Xcode.
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.
hello i am new to apple ecosystem and development i have some coding experience with c# now i like to develop my game for iphone 16 and up(due to ability to run ai models) but i am having hard time figuring out what to use there is a lot of resources for scene-kit but on its doc page it says its deprecated so i look at the reality-kit docs and tutorials and its strictly tells how to develop for visionos and i am really confused about this since there is no tutorials that shows how to develop a game for ios with reality-kit that does not focus visionos. i just want to develop for iphone 16 and up but i cant find resources focuses at that.
Topic:
Graphics & Games
SubTopic:
RealityKit
Hi all,
I've developed some code that enables an arcball camera interaction with my scene. I've done this using components and systems. The implementation feels a bit messy as I've got gesture code on my realityView, and then a bunch of other code that uses those gesture inputs in my component and system.
Is there a demo app, or some example code that shows a nice way to encapsulate these things in to one item for custom cameras, something like Apple's .realityViewCameraControls(.orbit)
If not can anyone recommend an approach to take?
Hello Apple team,
I'm working on an iOS AR app using SwiftUI and RealityKit,
and I was wondering if the Cinematic API can be used with a RealityKit scene. I’d like to achieve a shallow depth of field while keeping the 3D asset in focus, and vice versa.
Thanks!
I have been tasked with creating content for the Apple Vision Pro. Just the 3D content and animation, not the programming end of things.
I can't seem to get any kind of mesh deformation animation to import into Reality Composer Pro. By that I mean bones/skin, or even point cache.
I work on PC, and my main software is 3DS Max, but I'm borrowing an iMac for this job, and was instructed to use RCP on it for testing before handing things off to the programmer. My files open and play fine in other USD programs, like Omniverse, or USD View, just not Reality Composer Pro.
I've seen the dinosaur demo in AVP, so I know mesh deformation is possible. If there are other essential tools that might make this possible, I have not been made aware of them.
I am experimenting with bouncing things off of Blender, in case that exports better, but not really having luck there either -though my results are different.
Thanks.
Topic:
Graphics & Games
SubTopic:
RealityKit
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()
}
}
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)")
}
}
}
}
after launching a nearby exoerience on quick look or inside our app, all the user in the group watch sometimes teh model blinking abd becoming transparet...
... just one user hasnt the issue, either the one who launched shareplay or the user who force align the immersive space in front
weird
I implemented an EntityAction to change the baseColor tint - and had it working on VisionOS 2.x.
import RealityKit
import UIKit
typealias Float4 = SIMD4<Float>
extension UIColor {
var float4: Float4 {
if
cgColor.numberOfComponents == 4,
let c = cgColor.components
{
Float4(Float(c[0]), Float(c[1]), Float(c[2]), Float(c[3]))
} else {
Float4()
}
}
}
struct ColourAction: EntityAction {
// MARK: - PUBLIC PROPERTIES
let startColour: Float4
let targetColour: Float4
// MARK: - PUBLIC COMPUTED PROPERTIES
var animatedValueType: (any AnimatableData.Type)? { Float4.self }
// MARK: - INITIATION
init(startColour: UIColor, targetColour: UIColor) {
self.startColour = startColour.float4
self.targetColour = targetColour.float4
}
// MARK: - PUBLIC STATIC FUNCTIONS
@MainActor static func registerEntityAction() {
ColourAction.subscribe(to: .updated) { event in
guard let animationState = event.animationState else { return }
let interpolatedColour = event.action.startColour.mixedWith(event.action.targetColour, by: Float(animationState.normalizedTime))
animationState.storeAnimatedValue(interpolatedColour)
}
}
}
extension Entity {
// MARK: - PUBLIC FUNCTIONS
func changeColourTo(_ targetColour: UIColor, duration: Double) {
guard
let modelComponent = components[ModelComponent.self],
let material = modelComponent.materials.first as? PhysicallyBasedMaterial
else {
return
}
let colourAction = ColourAction(startColour: material.baseColor.tint, targetColour: targetColour)
if let colourAnimation = try? AnimationResource.makeActionAnimation(for: colourAction, duration: duration, bindTarget: .material(0).baseColorTint) {
playAnimation(colourAnimation)
}
}
}
This doesn't work in VisionOS 26. My current fix is to directly set the material base colour - but this feels like the wrong approach:
@MainActor static func registerEntityAction() {
ColourAction.subscribe(to: .updated) { event in
guard
let animationState = event.animationState,
let entity = event.targetEntity,
let modelComponent = entity.components[ModelComponent.self],
var material = modelComponent.materials.first as? PhysicallyBasedMaterial
else { return }
let interpolatedColour = event.action.startColour.mixedWith(event.action.targetColour, by: Float(animationState.normalizedTime))
material.baseColor.tint = UIColor(interpolatedColour)
entity.components[ModelComponent.self]?.materials[0] = material
animationState.storeAnimatedValue(interpolatedColour)
}
}
So before I raise this as a bug, was I doing anything wrong in the former version and got lucky? Is there a better approach?
Hello, I’m porting my UIKit/SceneKit app to SwiftUI/RealityKit and I’m wondering how to change the camera target programmatically. I created a simple scene in Reality Composer Pro with two spheres. My goal is straightforward: when the user taps a sphere, the camera should look at it as the main target.
Following Apple’s videos, I implemented the .gesture modifier and it is printing the tapped sphere correctly, but updating my targetEntity state doesn’t change anything, so the camera won't update its target. Is there a way to access the scene content at that level? Or what else should I do?
Here’s my current code implementation:
Thanks!