Hello,
There are three issues I am running into with a default template project + additional minimal code changes:
the Sphere_Left entity always overlaps the Sphere_Right entity.
when I release the Sphere_Left entity, it does not remain sticking to the Sphere_Right entity
when I release the Sphere_Left entity, it distances itself from the Sphere_Right entity
When I manipulate the Sphere_Right entity, these above 3 issues do not occur: I get a correct and expected behavior.
These issues are simple to replicate:
Create a new project in XCode
Choose visionOS -> App, then click Next
Name your project, and leave all other options as defaults: Initial Scene: Window, Immersive Space Renderer: RealityKit, Immersive Space: Mixed, then click Next
Save you project anywhere...
Replace the entire ImmersiveView.swift file with the below code.
Run.
Try to manipulate the left sphere, you should get the same issues I mentioned above
If you restart the project, and manipulate only the right sphere, you should get the correct expected behaviors, and no issues.
I am running this in macOS 26, XCode 26, on visionOS 26, all released lately.
ImmersiveView Code:
//
// ImmersiveView.swift
//
import OSLog
import SwiftUI
import RealityKit
import RealityKitContent
struct ImmersiveView: View {
private let logger = Logger(subsystem: "com.testentitiessticktogether", category: "ImmersiveView")
@State var collisionBeganUnfiltered: EventSubscription?
var body: some View {
RealityView { content in
// Add the initial RealityKit content
if let immersiveContentEntity = try? await Entity(named: "Immersive", in: realityKitContentBundle) {
content.add(immersiveContentEntity)
// Add manipulation components
setupManipulationComponents(in: immersiveContentEntity)
collisionBeganUnfiltered = content.subscribe(to: CollisionEvents.Began.self) { collisionEvent in
Task { @MainActor in
handleCollision(entityA: collisionEvent.entityA, entityB: collisionEvent.entityB)
}
}
}
}
}
private func setupManipulationComponents(in rootEntity: Entity) {
logger.info("\(#function) \(#line) ")
let sphereNames = ["Sphere_Left", "Sphere_Right"]
for name in sphereNames {
guard let sphere = rootEntity.findEntity(named: name) else {
logger.error("\(#function) \(#line) Failed to find \(name) entity")
assertionFailure("Failed to find \(name) entity")
continue
}
ManipulationComponent.configureEntity(sphere)
var manipulationComponent = ManipulationComponent()
manipulationComponent.releaseBehavior = .stay
sphere.components.set(manipulationComponent)
}
logger.info("\(#function) \(#line) Successfully set up manipulation components")
}
private func handleCollision(entityA: Entity, entityB: Entity) {
logger.info("\(#function) \(#line) Collision between \(entityA.name) and \(entityB.name)")
guard entityA !== entityB else { return }
if entityB.isAncestor(of: entityA) {
logger.debug("\(#function) \(#line) \(entityA.name) already under \(entityB.name); skipping reparent")
return
}
if entityA.isAncestor(of: entityB) {
logger.info("\(#function) \(#line) Skip reparent: \(entityA.name) is an ancestor of \(entityB.name)")
return
}
reparentEntities(child: entityA, parent: entityB)
entityA.components[ParticleEmitterComponent.self]?.burst()
}
private func reparentEntities(child: Entity, parent: Entity) {
let childBounds = child.visualBounds(relativeTo: nil)
let parentBounds = parent.visualBounds(relativeTo: nil)
let maxEntityWidth = max(childBounds.extents.x, parentBounds.extents.x)
let childPosition = child.position(relativeTo: nil)
let parentPosition = parent.position(relativeTo: nil)
let currentDistance = distance(childPosition, parentPosition)
child.setParent(parent, preservingWorldTransform: true)
logger.info("\(#function) \(#line) Set \(child.name) parent to \(parent.name)")
child.components.remove(ManipulationComponent.self)
logger.info("\(#function) \(#line) Removed ManipulationComponent from child \(child.name)")
if currentDistance > maxEntityWidth {
let direction = normalize(childPosition - parentPosition)
let newPosition = parentPosition + direction * maxEntityWidth
child.setPosition(newPosition - parentPosition, relativeTo: parent)
logger.info("\(#function) \(#line) Adjusted position: distance was \(currentDistance), now \(maxEntityWidth)")
}
}
}
fileprivate extension Entity {
func isAncestor(of other: Entity) -> Bool {
var current: Entity? = other.parent
while let node = current {
if node === self { return true }
current = node.parent
}
return false
}
}
#Preview(immersionStyle: .mixed) {
ImmersiveView()
.environment(AppModel())
}
