I’ve been having some issues removing anchors. I can add anchors with no issue. They will be there the next time I run the scene. I can also get updates when ARKit sends them. I can remove anchors, but not all the time. The method I’m using is to call removeAnchor() on the data provider.
worldTracking.removeAnchor(forID: uuid)
// Yes, I have also tried `removeAnchor(_ worldAnchor: WorldAnchor)`
This works if there are more than one anchor in a scene. When I’m down to one remaining anchor, I can remove it. It seems to succeed (does not raise an error) but the next time I run the scene the removed anchor is back. This only happens when there is only one remaining anchor.
do {
// This always run, but it doesn't seem to "save" the removal when there is only one anchor left.
try await worldTracking.removeAnchor(forID: uuid)
} catch {
// I have never seen this block fire!
print("Failed to remove world anchor \(uuid) with error: \(error).")
}
I posted a video on my website if you want to see it happening.
https://stepinto.vision/labs/lab-051-issues-with-world-tracking/
Here is the full code. Can you see if I’m doing something wrong? Is this a bug?
struct Lab051: View {
@State var session = ARKitSession()
@State var worldTracking = WorldTrackingProvider()
@State var worldAnchorEntities: [UUID: Entity] = [:]
@State var placement = Entity()
@State var subject : ModelEntity = {
let subject = ModelEntity(
mesh: .generateSphere(radius: 0.06),
materials: [SimpleMaterial(color: .stepRed, isMetallic: false)])
subject.setPosition([0, 0, 0], relativeTo: nil)
let collision = CollisionComponent(shapes: [.generateSphere(radius: 0.06)])
let input = InputTargetComponent()
subject.components.set([collision, input])
return subject
}()
var body: some View {
RealityView { content in
guard let scene = try? await Entity(named: "WorldTracking", in: realityKitContentBundle) else { return }
content.add(scene)
if let placementEntity = scene.findEntity(named: "PlacementPreview") {
placement = placementEntity
}
} update: { content in
for (_, entity) in worldAnchorEntities {
if !content.entities.contains(entity) {
content.add(entity)
}
}
}
.modifier(DragGestureImproved())
.gesture(tapGesture)
.task {
try! await setupAndRunWorldTracking()
}
}
var tapGesture: some Gesture {
TapGesture()
.targetedToAnyEntity()
.onEnded { value in
if value.entity.name == "PlacementPreview" {
// If we tapped the placement preview cube, create an anchor
Task {
let anchor = WorldAnchor(originFromAnchorTransform: value.entity.transformMatrix(relativeTo: nil))
try await worldTracking.addAnchor(anchor)
}
} else {
Task {
// Get the UUID we stored on the entity
let uuid = UUID(uuidString: value.entity.name) ?? UUID()
do {
try await worldTracking.removeAnchor(forID: uuid)
} catch {
print("Failed to remove world anchor \(uuid) with error: \(error).")
}
}
}
}
}
func setupAndRunWorldTracking() async throws {
if WorldTrackingProvider.isSupported {
do {
try await session.run([worldTracking])
for await update in worldTracking.anchorUpdates {
switch update.event {
case .added:
let subjectClone = subject.clone(recursive: true)
subjectClone.isEnabled = true
subjectClone.name = update.anchor.id.uuidString
subjectClone.transform = Transform(matrix: update.anchor.originFromAnchorTransform)
worldAnchorEntities[update.anchor.id] = subjectClone
print("🟢 Anchor added \(update.anchor.id)")
case .updated:
guard let entity = worldAnchorEntities[update.anchor.id] else {
print("No entity found to update for anchor \(update.anchor.id)")
return
}
entity.transform = Transform(matrix: update.anchor.originFromAnchorTransform)
print("🔵 Anchor updated \(update.anchor.id)")
case .removed:
worldAnchorEntities[update.anchor.id]?.removeFromParent()
worldAnchorEntities.removeValue(forKey: update.anchor.id)
print("🔴 Anchor removed \(update.anchor.id)")
if let remainingAnchors = await worldTracking.allAnchors {
print("Remaining Anchors: \(remainingAnchors.count)")
}
}
}
} catch {
print("ARKit session error \(error)")
}
}
}
}
Discuss spatial computing on Apple platforms and how to design and build an entirely new universe of apps and games for Apple Vision Pro.
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Goal: To render in an apple vision pro app, the solid-mechanics 3D simulation results coming form an FEA code.
Starting point: I have surface vtks with deformations on each node. Each time step has a a mesh with the nodal coordinates. This is straighforward translatable to a usd MeshSequence. Unfortunately, the results cannot be simplified to a scaling o linear transformation as you would do with other game-oriented animations.
Tools: Right now, I am using Xcode and reality composer pro (RCP) to build the scenes.
Technical limitations: I am aware that RCP can do animations with BlendMesh and skeletons and that MeshSequence is not a problem.
Progress:
Coverting to the sequence of vtk meshes to a usd MeshSequence is straighforward. This animates correctly in Preview and Blender (see screenshot).
I managed to convert from MeshSequence to multiple keys and BlendMesh. This also animates correctly in Blender and preview. Unfortunately, the BlendMesh of multiple blended meshes shows a zero animation time in RCP (see screenshot below)
Also, see below usda file scheme for the animation. Of course I am not showing full vectors such as faceVertexCounts, faceVertexIndex, normals.
Question: what is the right set up to create a BlendMesh animation that RCP will correctly import and animate, form a set of Meshes or multiple key shapes?
Blender animation
Time zero RCP "animations"
#usda 1.0
(
defaultPrim = "BlendMeshRoot"
doc = "Blender v4.5.3 LTS"
endTimeCode = 48
framesPerSecond = 24
metersPerUnit = 1
startTimeCode = 0
timeCodesPerSecond = 24
upAxis = "Z"
)
def Xform "BlendMeshRoot" (
customData = {
dictionary Blender = {
bool generated = 1
}
}
)
{
def SkelRoot "Mesh"
{
custom string userProperties:blender:object_name = "Mesh"
float3 xformOp:rotateXYZ = (89.99999, -0, 0)
float3 xformOp:scale = (0.009999999, 0.01, 0.01)
double3 xformOp:translate = (0, 0, 0)
uniform token[] xformOpOrder = ["xformOp:translate", "xformOp:rotateXYZ", "xformOp:scale"]
def Mesh "Mesh" (
active = true
prepend apiSchemas = ["MaterialBindingAPI", "SkelBindingAPI"]
)
{
uniform bool doubleSided = 1
float3[] extent = [(25.091871, -34.121277, -13.298501), (299.94482, 245.10088, 202.35126)]
int[] faceVertexCounts = [3, 3, ...
int[] faceVertexIndices = [0, 10293, ...
rel material:binding = </BlendMeshRoot/_materials/MeshSequence_Default>
normal3f[] normals = [(-0.3632836, -0.9102419, -0.19870725), ....
point3f[] points = [(244.41148, 155.42062, 70.454926),.....
float3[] primvars:node_displacement = [(93.54703, 110.9341, 48.37992)....
float3[] primvars:Normals = [(-0.0050530406, -0.9910114, -0.13368203),...
int[] primvars:skel:jointIndices = [0, 0, 0, 0, 0 ...
float[] primvars:skel:jointWeights = [1, 1, 1, 1, 1...
uniform token[] skel:blendShapes = ["frame_0000", "frame_0001", "frame_0002", "frame_0003", "frame_0004", "frame_0005"]
rel skel:blendShapeTargets = [
</BlendMeshRoot/Mesh/Mesh/frame_0000>,
.......
</BlendMeshRoot/Mesh/Mesh/frame_0005>,
]
prepend rel skel:skeleton = </BlendMeshRoot/Mesh/Skel>
uniform token subdivisionScheme = "none"
custom string userProperties:blender:data_name = "Mesh"
custom float userProperties:originalTime
float userProperties:originalTime.timeSamples = {
0: 0,
}
def BlendShape "frame_0000"
{
uniform vector3f[] offsets = [(0, 0, 0), (0, 0, 0),.....
uniform int[] pointIndices = [0, 1, 2, .....
}
.....
.....
#### BlendShape frame to 0005
.....
def Skeleton "Skel" (
prepend apiSchemas = ["SkelBindingAPI"]
)
{
uniform matrix4d[] bindTransforms = [( (1, 0, 0, 0), (0, 1, 0, 0), (0, 0, 1, 0), (0, 0, 0, 1) )]
uniform token[] joints = ["joint1"]
uniform matrix4d[] restTransforms = [( (1, 0, 0, 0), (0, 1, 0, 0), (0, 0, 1, 0), (0, 0, 0, 1) )]
prepend rel skel:animationSource = </BlendMeshRoot/Mesh/Skel/Anim>
def SkelAnimation "Anim"
{
uniform token[] blendShapes = ["frame_0000", "frame_0001", "frame_0002", "frame_0003", "frame_0004", "frame_0005"]
float[] blendShapeWeights.timeSamples = {
0: [1, 0, 0, 0, 0, 0],
1: [0.9697085, 0.03029152, 0, 0, 0, 0],
2: [0.88787615, 0.11212383, 0, 0, 0, 0],
.....
46: [0, 0, 0, 0, 0.11212379, 0.8878762],
47: [0, 0, 0, 0, 0.030291557, 0.96970844],
48: [0, 0, 0, 0, 0, 1],
}
}
}
}
def Scope "_materials"
{
def Material "MeshSequence_Default"
{
token outputs:surface.connect = </BlendMeshRoot/_materials/MeshSequence_Default/Principled_BSDF.outputs:surface>
custom string userProperties:blender:data_name = "MeshSequence_Default"
def Shader "Principled_BSDF"
{
uniform token info:id = "UsdPreviewSurface"
float inputs:clearcoat = 0
float inputs:clearcoatRoughness = 0.03
color3f inputs:diffuseColor = (0.8, 0.4, 0.3)
float inputs:ior = 1.5
float inputs:metallic = 0
float inputs:opacity = 1
float inputs:roughness = 0.5
float inputs:specular = 0.2
token outputs:surface
}
}
}
def Scope "AnimationClips"
{
custom rel animations = </BlendMeshRoot/Mesh/Skel/Anim>
}
def RealityKitComponent "AnimationLibrary"
{
custom rel animations = </BlendMeshRoot/Mesh/Skel/Anim>
custom token info:id = "RealityKit.AnimationLibrary"
custom double realitykit:approximateDuration = 2
custom double[] realitykit:clipDurations = [2]
custom string[] realitykit:clipNames = ["Anim"]
custom rel realitykit:clipTargets = </BlendMeshRoot/Mesh/Skel/Anim>
custom double realitykit:frameRate = 24
custom bool realitykit:isAnimationLibrary = 1
}
}
Topic:
Spatial Computing
SubTopic:
Reality Composer Pro
Tags:
Swift Packages
Developer Tools
Reality Converter
Reality Composer
The new Mac virtual display feature on visionOS 2 offers a curved/panoramic window. I was wondering if this is simply a property that can be applied to a window, or if it involves an immersive mode or SceneKit/RealityKit?
Hi everyone! I am working on AR app and wanted to implement object occlusion because it removes drift pretty much from the object. This working great with RealityKit sample But I am unable to replicate such behaviour it with scenekit. Because scenekit does not offer object occlusion. Can we say scenekit is getting depricated, and we should re-write app in RealityKit (which is obviously a big task)?
What is the reason the hand-tracking joints have these axes? I'm trying to create a virtual hands model and that's a mess.
This post documents an issue I reported in feedback FB19610114 and see if anyone knows of a workaround. Here is a copy of the feedback.
Short version
Manipulation (SwiftUI OR RealityKit) fails to translate entities after changing rooms. By changing rooms, I mean a human wearing an Apple Vision Pro leaving one room and entering another room. Once this issue occurs, it impacts all apps that use these features. A device restart is the only solution I have to fix it.
Feedback FB19610114
This is an odd one. I'm using the new Manipulation Component in visionOS 26. Most of the time this works well. Sometime it stops working and when it does the only way to get it working again is to reboot the headset.
When this happens, I can continue to rotate and scale items, but translation no longer works. It is as if the item is stuck to a fixed point in the parent scene (window, volume, etc). When this bug occurs, it affects every app across the entire operating system that is using manipulation, including the RealityKit component AND the SwiftUI version. This is not limited to one app and is not limited to apps that I am working on. Once this error occurs, it affects literally any application across the operating system that is using this API, including apps from Apple.
I won't speculate on the cause of this, but I do know of one way where I can always get it to happen.
Here is how to reproduce it:
Make an Xcode project with a single entity that uses the Manipulation Component. There is no need to customize the configuration of this component. The default implementation will work.
Build and run this app on device. You can keep running from device or quit and launch the app like normal on device.
Open the app and manipulate the entity - it should work as expected.
Physically walk into another room. It is vital that you leave the current room that you are in and enter a different room entirely.
Use the digital crown to recenter your view and bring your window or volume to you.
Test the manipulation on the entity again - it should still be working as expected at this point.
Physically, move yourself and your headset into the original room where you started.
Use the digital crown to recenter your view and bring your window or volume to you.
Test the manipulation on the entity again - you should now see the issue.
When I follow the steps above, then 100% of the time manipulation translation stops working at this point. It will impact any application using this API. The only way to fix it is to restart my headset.
A few points to keep in mind
It does not matter if an app is actively being run from Xcode.
When this occurs, it impacts every single app, not just one.
When this occurs, rotation and scaling continue to work, but the entity/view cannot be translated.
This impacts BOTH the SwiftUI version and the RealityKit version.
When this occurs, the only way to "fix" it is to reboot the device.
Hello, I've pre-ordered the Logitech Muse with hopes of developing with it, but have yet to find any documentation relating to the capabilities it will have/any APIs that will be available to take advantage of the Muse. Is anyone aware of what might become available?
Thank you in advance.
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
How can I request access to Enterprise API for VisionPro with an individual developer account? I wanted it for learning and testing
The issue reproducible with empty project. When you run it and tap "Open immersive space" it takes a couple of minutes to respond. The issue only reproducible on real device with debugger attached. Reproducible other developers too (not specific to my environment). Issue doesn't exists in Xcode 16.
Afer initial long delay subsequent opens works fine.
Console logs:
nw_socket_copy_info [C1:2] getsockopt TCP_INFO failed [102: Operation not supported on socket]
nw_socket_copy_info getsockopt TCP_INFO failed [102: Operation not supported on socket]
Failed to set dependencies on asset 9303749952624825765 because NetworkAssetManager does not have an asset entity for that id.
void * _Nullable NSMapGet(NSMapTable * _Nonnull, const void * _Nullable): map table argument is NULL
PSO compilation completed for driver shader copyFromBufferToTexture so=0 sbpr=256 sbpi=16384 ss=(64, 64, 1) p=70 sc=1 ds=0 dl=0 do=(0, 0, 0) in 1997
XPC connection interrupted
<<<< FigAudioSession(AV) >>>> audioSessionAVAudioSession_CopyMXSessionProperty signalled err=-19224 (kFigAudioSessionError_UnsupportedOperation) (getMXSessionProperty unsupported) at FigAudioSession_AVAudioSession.m:606
Failed to load item AXCodeItem<0x14706f250> [Rank:6000] SpringBoardUIServices [AXBundle name:/System/Library/AccessibilityBundles/SpringBoardUIServices.axbundle/SpringBoardUIServices] [Platforms and Targets:{ iOS = SpringBoardUIServices; } Framework] [Excluded: (null)]. error: Error Domain=AXLoading Code=0 "URL does not exist: file:///System/Library/AccessibilityBundles/SpringBoardUIServices.axbundle" UserInfo={NSLocalizedDescription=URL does not exist: file:///System/Library/AccessibilityBundles/SpringBoardUIServices.axbundle}
Failed to load item AXCodeItem<0x14706f250> [Rank:6000] SpringBoardUIServices [AXBundle name:/System/Library/AccessibilityBundles/SpringBoardUIServices.axbundle/SpringBoardUIServices] [Platforms and Targets:{ iOS = SpringBoardUIServices; } Framework] [Excluded: (null)]. error: Error Domain=AXLoading Code=0 "URL does not exist: file:///System/Library/AccessibilityBundles/SpringBoardUIServices.axbundle" UserInfo={NSLocalizedDescription=URL does not exist: file:///System/Library/AccessibilityBundles/SpringBoardUIServices.axbundle}
[b30780-MRUIFeedbackTypeButtonWithBackgroundTouchDown] Playback timed out before completion (after 3111 ms)
Failed to set dependencies on asset 7089614247973236977 because NetworkAssetManager does not have an asset entity for that id.
Hi, I'm very new to 3D and am currently porting a SwiftUI iOS app to visionOS 2.0.
I saw WWDC24 feature Blender in multiple spatial videos, and have begun integrating Blender models and animations into my VisionOS app (I would also like to integrate skeletons and programmatic rigging, more on that later).
I'm wondering if there are “Best Practices” for this workflow - from Blender to USD to RCP 2.0 to visionOS 2 in Xcode. I’ve cobbled together the following that has some obvious holes:
I’ve been able to find some pre-rigged and pre-animated models online that can serve as a great starting point. As a reference, here is a free model from SketchFab - a simple rigged skeleton with 6 built in animations:
https://sketchfab.com/3d-models/skeleton-character-low-poly-8856e0138f424d68a8e0b40e185951f6
When exporting to USD from Blender, I haven’t been able to export more than one animation per USD file. Is there a workflow to export multiple animations in a single USDC file, or is this just not possible?
As a temporary workaround, here is a python script I’ve been using to loop through all Blender animations, and export a model for each animation:
import bpy
import os
# Set the directory where you want to save the USD files
output_directory = “/path/to/export”
# Ensure the directory exists
if not os.path.exists(output_directory):
os.makedirs(output_directory)
# Function to export current scene as USD
def export_scene_as_usd(output_path, start_frame, end_frame):
bpy.context.scene.frame_start = start_frame
bpy.context.scene.frame_end = end_frame
# Export the scene as a USD file
bpy.ops.wm.usd_export(
filepath=output_path,
export_animation=True
)
# Save the current scene name
original_scene = bpy.context.scene.name
# Iterate through each action and export it as a USD file
for action in bpy.data.actions:
# Create a new scene for each action
bpy.context.window.scene = bpy.data.scenes[original_scene].copy()
new_scene = bpy.context.scene
# Link the action to all relevant objects
for obj in new_scene.objects:
if obj.animation_data is not None:
obj.animation_data.action = action
# Determine the frame range for the action
start_frame, end_frame = action.frame_range
# Export the scene as a USD file
output_path = os.path.join(output_directory, f"{action.name}.usdc")
export_scene_as_usd(output_path, int(start_frame), int(end_frame))
# Delete the temporary scene to free memory
bpy.data.scenes.remove(new_scene)
print("Export completed.")
I have also been able to successfully export rigging armatures as a single Skeleton - each “bone” showing getting imported into Reality Composer Pro 2.0 when exporting/importing manually.
I would like to have all of these animations available in a single scene to be used in a RealityView in visionOS - so I have placed all animation models in a RCP scene and created named Timeline Action animations for each, showing the correct model and hiding the rest when triggering specific animations.
I apply materials/textures to each so they appear the same, using Shader Graph.
Then in SwiftUI I use notifications (as shown here - https://forums.developer.apple.com/forums/thread/756978) to trigger each RCP Timeline Action animation from code.
Two questions:
Is there a better way than to have multiple models of the same skeleton - each with a different animation - in a scene to be able to trigger multiple animations? Or would this require recreating Blender animations using skeleton rigging and keyframes from within RCP Timelines?
If I want to programmatically create custom animations and move parts of the skeleton/armatures - do I need to do this by defining custom components in RCP, using IKRig and define movement of each of the “bones” in Xcode?
I’m looking for any tips/tricks/workflow from experienced engineers or 3D artists that can create a more efficient/optimized workflow using Blender, USD, RCP 2 and visionOS 2 with SwiftUI.
Thanks so much, I appreciate any help! I am very excited about all the new tools that keep evolving to make spatial apps really fun to build!
Topic:
Spatial Computing
SubTopic:
Reality Composer Pro
Tags:
RealityKit
Reality Composer Pro
visionOS
是对原本VisionPro每个App的内存限制做了扩展嘛?放宽了内存限制么?
At a recent community meeting we were wondering how Apple creates this soft-edge effect around the occlusion cutouts. We see this effect on keyboard cutouts, iPhone cutouts, and in progressive spaces.
An example: Notice the soft edged around the occlusion cutout for the keyboard
One of our members created some Shader Graph materials to explore soft edges. These work by sending data into the opacity channel of the PreviewSurface node.
Unfortunately, the Occlusion Surface nodes lack any sort of input. If you know how to blend these concepts with RealityKit Occlusion, please let us know!
The WWDC25 video and notes titled “Learn About Apple Immersive Video Technologies” introduced the Apple Spatial Audio Format (ASAF) and codec (APAC). However, despite references throughout on using immersive video, there is scant information on ASAF/APAC (including no code examples and no framework references), and I’ve found no documentation in Apple’s APIs/Frameworks about its implementation and use months on.
I want to leverage ambisonic audio in my app. I don’t want to write a custom AU if APAC will be opened up to developers. If you read the notes below along with the iPhone 17 advertising (“Video is captured with Spatial Audio for immersive listening”), it sounds like this is very much a live feature in iOS26.
Anyone know the state of play? I’m across how the PHASE engine works, which is unrelated to what I’m asking about here.
Original quote from video referenced above: “ASAF enables truly externalized audio experiences by ensuring acoustic cues are used to render the audio. It’s composed of new metadata coupled with linear PCM, and a powerful new spatial renderer that’s built into Apple platforms. It produces high resolution Spatial Audio through numerous point sources and high resolution sound scenes, or higher order ambisonics.”
”ASAF is carried inside of broadcast Wave files with linear PCM signals and metadata. You typically use ASAF in production, and to stream ASAF audio, you will need to encode that audio as an mp4 APAC file.”
”APAC efficiently distributes ASAF, and APAC is required for any Apple immersive video experience. APAC playback is available on all Apple platforms except watchOS, and supports Channels, Objects, Higher Order Ambisonics, Dialogue, Binaural audio, interactive elements, as well as provisioning for extendable metadata.”
Topic:
Spatial Computing
SubTopic:
General
I would like to translate info in a three.js based web app as a 3D model in a volumetric window. Is it possible to do this in a similar manner as loading a web page in a WKWebView?
The AR based app I am working on right now is experiencing an issue. Sometimes, the AR session fails with a call to my ARSessionObserver's session(_ session: ARSession, didFailWithError error: Error)
with the following error:
Error Domain=com.apple.arkit.error
Code=102 "Required sensor failed."
NSLocalizedFailureReason="A sensor failed to deliver the required input.,"
NSLocalizedRecoverySuggestion="Make sure that the application has the required privacy settings."
The underlying error seems to point to the CoreMotion framework:
Domain=CMErrorDomain
Code=102 "(null)
Some people seem to have experienced this issue and solved it by making sure that the Compass Calibration switch is ON in Settings > Privacy > Location Services > System Services.
For context, the ARWorldTrackingConfiguration.worldAlignment is set to .gravity
The thing is it is already ON when I experience this issue.
I also noticed that this issue happens way more often on the iPhone 16e than in any other device.
Has anyone had similar experiences? I am looking for a way to prevent this error from happening (ideally) or handling in a way that does not affect the user. Any help is appreciated
I'm developing a VisionOS app with bouncing ball physics and struggling to achieve natural bouncing behavior using RealityKit's physics system. Despite following Apple's recommended parameters, the ball loses significant energy on each bounce and doesn't behave like a real basketball, tennis ball, or football would.
With identical physics parameters (restitution = 1.0), RealityKit shows significant energy loss. I've had to implement a custom physics system to compensate, but I want to use native RealityKit physics. It's impossible to make it work by applying custom impulses.
Ball Physics Setup (Following Apple Forum Recommendations)
// From PhysicsManager.swift
private func createBallEntityRealityKit() -> Entity {
let ballRadius: Float = 0.05
let ballEntity = Entity()
ballEntity.name = "bouncingBall"
// Mesh and material
let mesh = MeshResource.generateSphere(radius: ballRadius)
var material = PhysicallyBasedMaterial()
material.baseColor = .init(tint: .cyan)
material.roughness = .float(0.3)
material.metallic = .float(0.8)
ballEntity.components.set(ModelComponent(mesh: mesh, materials: [material]))
// Physics setup from Apple Developer Forums
let physics = PhysicsBodyComponent(
massProperties: .init(mass: 0.624), // Seems too heavy for 5cm ball
material: PhysicsMaterialResource.generate(
staticFriction: 0.8,
dynamicFriction: 0.6,
restitution: 1.0 // Perfect elasticity, yet still loses energy
),
mode: .dynamic
)
ballEntity.components.set(physics)
ballEntity.components.set(PhysicsMotionComponent())
// Collision setup
let collisionShape = ShapeResource.generateSphere(radius: ballRadius)
ballEntity.components.set(CollisionComponent(shapes: [collisionShape]))
return ballEntity
}
Ground Plane Physics
// From GroundPlaneView.swift
let groundPhysics = PhysicsBodyComponent(
massProperties: .init(mass: 1000),
material: PhysicsMaterialResource.generate(
staticFriction: 0.7,
dynamicFriction: 0.6,
restitution: 1.0 // Perfect bounce
),
mode: .static
)
entity.components.set(groundPhysics)
Wall Physics
// From WalledBoxManager.swift
let wallPhysics = PhysicsBodyComponent(
massProperties: .init(mass: 1000),
material: PhysicsMaterialResource.generate(
staticFriction: 0.7,
dynamicFriction: 0.6,
restitution: 0.85 // Slightly less than ground
),
mode: .static
)
wall.components.set(wallPhysics)
Collision Detection
// From GroundPlaneView.swift
content.subscribe(to: CollisionEvents.Began.self) { event in
guard physicsMode == .realityKit else { return }
let currentTime = Date().timeIntervalSince1970
guard currentTime - lastCollisionTime > 0.1 else { return }
if event.entityA.name == "bouncingBall" || event.entityB.name == "bouncingBall" {
let normal = event.collision.normal
// Distinguish between wall and ground collisions
if abs(normal.y) < 0.3 { // Wall bounce
print("Wall collision detected")
} else if normal.y > 0.7 { // Ground bounce
print("Ground collision detected")
}
lastCollisionTime = currentTime
}
}
Issues Observed
Energy Loss: Despite restitution = 1.0 (perfect elasticity), the ball loses ~20-30% energy per bounce
Wall Sliding: Ball tends to slide down walls instead of bouncing naturally
No Damping Control: Comments mention damping values but they don't seem to affect the physics
Change in mass also doesn't do much.
Custom Physics System (Workaround)
I've implemented a custom physics system that manually calculates velocities and applies more realistic restitution values:
// From BouncingBallComponent.swift
struct BouncingBallComponent: Component {
var velocity: SIMD3<Float> = .zero
var angularVelocity: SIMD3<Float> = .zero
var bounceState: BounceState = .idle
var lastBounceTime: TimeInterval = 0
var bounceCount: Int = 0
var peakHeight: Float = 0
var totalFallDistance: Float = 0
enum BounceState {
case idle
case falling
case justBounced
case bouncing
case settled
}
}
Is this energy loss expected behavior in RealityKit, even with perfect restitution (1.0)?
Are there additional physics parameters (damping, solver iterations, etc.) that could improve bounce behavior?
Would switching to Unity be necessary for more realistic ball physics, or am I missing something in RealityKit?
Even in the last video here: https://stepinto.vision/example-code/collisions-physics-physics-material/ bounce of the ball is very unnatural - stops after 3-4 bounces. I apply custom impulses, but then if I have walls around the ball, it's almost impossible to make it look natural. I also saw this post https://developer.apple.com/forums/thread/759422 and ball is still not bouncing naturally.
Hi, I would like to train Gaussian splats from my object captures. So I need a pointcloud and camera positions together with the original photos taken to train GS In an app like postShot.
I could do this with Reality Capture, which supports exporting pointclouds and camera position but it does not do well with turntable photogrammetry.
While the Apple object capture API does produce really solid results with turntable images.
so my question is, can I export camera data from my object captures to use in another application? Or is there may be a plan to at this feature in the future?
It would be really helpful in creating ultra realistic, 3-D objects in Gaussian splat format.
Thanks for any isuggestions…
Hi Apple Team,
We noticed the following exciting changelog in the latest macOS 26 beta:
A new algorithm significantly improves PhotogrammetrySession reconstruction quality of low-texture objects not captured with the ObjectCaptureSession front end. It will be downloaded and cached once in the background when the PhotogrammetrySession is used at runtime. If network isn’t available at that time, the old low quality model will be used until the new one can be downloaded. There is no code change needed to get this improved model. (145220451)
However after trying this on the latest beta and running some tests we do not see any differences on objects with low textures such as single coloured surfaces. Is there anything we are missing? the machine is definitely connected to the internet but we have no way of knowing from the logs if the new model is being used?
thanks
When using RoomPlan to collect data and processing it with StructureBuilder, the app crashes.
Crash thread:
RoomScanCore.offlineFloorPlanGeneration
How should I deal with this issue? I’ve already implemented crash capture, but no crash was logged—the app just crashes directly.
RoomScanCore.offlineFloorPlanGeneration