Combining 2D and 3D views in an immersive app

At a glance

Project structure

Source bundle/
├── MultiDimensionalImmersiveContent/RainbowModel.swift  # RainbowModel, EntityData, ArchAttachmentColor
├── MultiDimensionalImmersiveContent/RainbowView.swift  # RainbowView
├── MultiDimensionalImmersiveContent/CALayerArch/CALayerArcView.swift  # CALayerArcView
├── MultiDimensionalImmersiveContent/MultiDimensionalImmersiveContentApp.swift  # MultiDimensionalImmersiveContentApp
├── MultiDimensionalImmersiveContent/SwiftUIArch/SwiftUIArcView.swift  # SwiftUIArcView, Arc
├── MultiDimensionalImmersiveContent/UIViewArch/UIViewArcView.swift  # UIViewArcView
├── Packages/RealityKitContent/Sources/RealityKitContent/RealityKitContent.swift
└── Packages/RealityKitContent/Package.realitycomposerpro/ProjectData/main.json  # authored RealityKit content

Structure observations

• The runtime boundary is ImmersiveSpace + SwiftUI/UIKit host; the tree is pruned to lifecycle, state, framework, rendering, and ECS files.
• The source is Swift; role-named types and feature folders separate the major responsibilities.
• Authored .reality, .rkassets, or Reality Composer Pro content is an implementation boundary; Swift loads or drives it rather than reproducing its entity graph.

Overall architecture

flowchart LR
    MultiDimensionalImmersiveContentApp_1["MultiDimensionalImmersiveContentApp"]
    ImmersiveSpace___SwiftUI_UIKit_host_2["ImmersiveSpace + SwiftUI/UIKit host"]
    RainbowView_3["RainbowView"]
    RainbowModel_4["RainbowModel"]
    RealityKit_entity_graph_5["RealityKit entity graph"]
    SwiftUI___UIKit_layers___RealityKit_6["SwiftUI + UIKit layers + RealityKit"]
    MultiDimensionalImmersiveContentApp_1 --> ImmersiveSpace___SwiftUI_UIKit_host_2
    ImmersiveSpace___SwiftUI_UIKit_host_2 --> RainbowView_3
    RainbowView_3 --> RainbowModel_4
    RainbowModel_4 --> RealityKit_entity_graph_5
    RealityKit_entity_graph_5 --> SwiftUI___UIKit_layers___RealityKit_6

Reference code

MultiDimensionalImmersiveContent/MultiDimensionalImmersiveContentApp.swift:11 — executable or app-lifecycle anchor.

struct MultiDimensionalImmersiveContentApp: App {
    var body: some Scene {
        ImmersiveSpace(id: "ImmersiveSpace") {
            RainbowView()
        }
    }
}

The diagram is a responsibility flow, not a claim that every adjacent node directly calls the next. It separates lifecycle, presentation, stable state, framework/session work, and the RealityKit entity graph.

Ownership and state

classDiagram
    RainbowView *-- RainbowModel : rainbowModel
    RainbowView *-- Entity : root
    RainbowModel *-- EntityData : plane
    CloudTapAttachment --> Entity : parent

Ownership evidence

MultiDimensionalImmersiveContent/RainbowView.swift:14 — representative stored state or nearest verified lifecycle anchor.

@MainActor struct RainbowView: View {
    // ...
    @State private var rainbowModel = RainbowModel()
    // ...
}

Ownership is intentionally narrow: environment, bindings, observed objects, weak links, and delegate callbacks do not prove lifetime ownership. Initialized stored services and wrapper-managed state do; entities added inside a RealityKit content closure belong to that entity graph.

Class and protocol design

The reviewed source defines no local substitution protocol. Its App, View, delegate, renderer, ARKit, and RealityKit conformances are framework-facing contracts, so this document does not label the whole app protocol-oriented.

Access control

No reviewed Swift access example uses fileprivate, private(set), open; declarations without a modifier are internal.

Reference code

MultiDimensionalImmersiveContent/RainbowView.swift:14 — representative visibility boundary.

    @State private var rainbowModel = RainbowModel()
    
    /// The root entity for the scene.
    private let root = Entity()
    
    @Environment(\.physicalMetrics) private var physicalMetrics

Logic ownership and placement

Design patterns

Naming conventions

• Role suffixes are evidence, not decoration: App: MultiDimensionalImmersiveContentApp; Model: RainbowModel; View: CALayerArcView, RainbowView, SwiftUIArcView, UIViewArcView.
• Protocols: no app-defined protocol in the reviewed source.
• Commands use verb-led methods: addAttachments, createArchAttachment, createAndPositionTapEntity, scaleAndPositionArches, createEntity, configureForTapGesture, didMoveToSuperview, layoutSubviews.
• Files and folders use primary-type or responsibility names such as Views, Models, Rendering, Components, Systems, Packages, or feature names where those boundaries exist.

Architecture takeaways

• Treat MultiDimensionalImmersiveContentApp as the owner of executable or scene lifecycle, not automatically as the owner of every entity created later.
• Keep view/controller input near presentation, but move sessions, reconstruction, capture, rendering, shared game state, or documents into stable owners when their lifetime exceeds one callback or render pass.
• Count authored Reality Composer Pro assets as implementation; the Swift shell is not the complete architecture.

Source map

• Official Apple documentation