Access child components in USDZ with XCode?

are you using a USDZ file or FBX? are you getting any errors?

This is the hierarchy i can see in XCode. I want to access the elements (FP[n] and Pivot when i placed the entity in the scene. however, i cant access them with the child function.

Here are some code snippets on how i place my object in the AR View. I place it by tapping on the screen and handle the tap with an ARView Coorinator. I use the focus entity package to define the anchor point for the model entity. Here, i want to access the information about the child elements, that should be places with the usdz file. As you can see I tried to print out the information, and tried some things. I can't figure out where the children are attached to.

`@objc func handleTap() { guard let view = self.view, let focusEntity = self.focusEntity else {return}

	if (!object.inScene) {
		object.anchorEntity = AnchorEntity()
		view.scene.anchors.append(object.anchorEntity!)
		object.modelEntity = try! ModelEntity.loadModel(named: object.fileName)
		object.modelEntity!.name = object.name

		object.anchorEntity!.position = focusEntity.position
		object.anchorEntity!.addChild(object.modelEntity!)
		
		print(object.modelEntity!.children)
		print(object.modelEntity!.components)

		object.inScene = true
		object.anchorPosition = object.anchorEntity!.transform.translation
		object.anchorRotation = object.anchorEntity!.transform.rotation
	}
	else {return}
}`

The "object" class contains the data i need to use in my whole app, it also tells the coordinator the file name and stores some other info:

` @MainActor class Object: ObservableObject {

let name: String = "Vase"
//let fileName: String = "flower_tulip.usdz"
let fileName: String = "Vase_FP.usdz"
let scale: SIMD3<Float> = SIMD3<Float>(0.1, 0.1, 0.1)

@Published var session: ARSession?

@Published var modelEntity: ModelEntity?
@Published var anchorEntity: AnchorEntity?
@Published var anchorPosition: SIMD3<Float>?
@Published var anchorRotation: simd_quatf?

@Published var deletionRequest: Bool = false
@Published var inScene: Bool = false


func changeObjectPosition(_ sender: Any, newPosition: SIMD3<Float>){
	self.anchorPosition = newPosition
	self.anchorEntity?.transform.translation = newPosition
}

func changeObjectRotation(_ sender: Any, newRotation: simd_quatf){
	self.anchorRotation = newRotation
	self.anchorEntity?.transform.rotation = newRotation
}

func enumerateChildren(_ sender: Any){
	let children = self.modelEntity!.children
	for (n, c) in children.enumerated() {
		print("\(n): '\(c)'")
	}
}

var deletion: Cancellable?

}`

I use scene reconstruction and depth in my ARView, since i work with an iPad Pro. But that does not have to do anything with the question.

I hope things got a bit clearer now

crap. this stupid site removed everything i had typed before i was finished.

anyway. i never used realitykit. but it seems you can access your hierarchy like this

modelEntity.model.mesh.contents.isntances, where instances is a collection (meshInstanceCollection) and you can access the members by string subscript which is the name of the nodes as a path name. for example

modelEntity.model.mesh.contents.isntances["Vase_FP/mod(i can't see this in your screengrab)/FP2"]

or you can iterate through the meshInstanceCollection with its methods mentioned in the documentation. there is also modelEntity.model.mesh.contents.models, but it came up with no visible descriptions on my console so i don't know what it does.

anyway, i hope this gets you closer.

edit: yes you had to go in the nested components, which is .model

Well, well.. I finally figured it out! I used ModelEntity in the code above to place the object, which is a subclass of Entity. However, ModelEntity does flatten the Hierarchy and only shows the geometry that is visible and flattens (combines) it to be one and only one instance. Thats why I was only getting SIMD4 for geometry_0. So I went back and loaded the model i want to place as Entity, which inherits from "HasHierarchy" ans "HasTransform". After that, I can just call "Entity.children" and It works just fine and shows all of the child elements as Entities.

What a ride. Hope it might help others that face the problem aswell. :)