Composing interactive 3D content with RealityKit and Reality Composer Pro

At a glance

Project structure

Source bundle/
└── RealityKitAnimation/
    ├── RealityKitAnimation/
    │   ├── RealityKitAnimationApp.swift
    │   ├── AppModel.swift
    │   ├── ContentView.swift
    │   ├── ImmersiveView.swift
    │   └── ToggleImmersiveSpaceButton.swift
    └── Packages/
        └── RealityKitContent/
            ├── Sources/
            │   └── RealityKitContent/
            │       ├── HeroRobotComponent.swift
            │       ├── HeroPlantComponent.swift
            │       ├── EntityMoverComponent.swift
            │       ├── StationaryRobotComponent.swift
            │       ├── HeroRobotComponentExtension.swift
            │       └── RealityKitContent.swift
            └── Package.swift

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Swift.
• The verified tree contains 4 project/configuration file(s) and 22 source declaration(s).

Overall architecture

flowchart LR
    N1["RealityKitAnimationApp"]
    N2["ContentView"]
    N3["AppModel"]
    N4["EntityMoverSystem"]
    N5["RealityKit / RealityKitContent APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4
    N4 --> N5

Reference code

RealityKitAnimation/RealityKitAnimation/RealityKitAnimationApp.swift:10 — architecture anchor

@main
struct RealityKitAnimationApp: App {

    @State private var appModel = AppModel()

    var body: some Scene {
        WindowGroup {
            ContentView()
                .environment(appModel)
                .volumeBaseplateVisibility(.visible)
        }
        .windowStyle(.volumetric)

        ImmersiveSpace(id: "ImmersiveSpace") {
            ImmersiveView()
                .environment(appModel)
                .onAppear {
                    appModel.immersiveSpaceState = .open
                }
                .onDisappear {
                    appModel.immersiveSpaceState = .closed
                }
        }
    }
}

Interpretation

The arrows summarize the source-visible entry, role-named types or folders, and framework direction; when nodes come from structural folders, the sequence is a high-level interpretation rather than proof that every adjacent node calls the next. Ownership is claimed only where the next section cites a stored property or assignment. The diagram is intentionally limited to the dominant path into RealityKit.

Ownership and state

classDiagram
    RealityKitAnimationApp *-- AppModel : appModel
    HeroRobotComponent *-- Float : ikTotalBlendTime
    HeroRobotRuntimeComponent o-- HeroRobotComponent : settingsSource
    HeroRobotRuntimeComponent o-- HeroRobotState : currentState

Ownership evidence

RealityKitAnimation/RealityKitAnimation/RealityKitAnimationApp.swift:13 — stored dependency or nearest verified ownership anchor

@main
struct RealityKitAnimationApp: App {
    // ...
    @State private var appModel = AppModel()
    // ...
}

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Concurrency, scheduling, and thread safety

Evidence limit: actor isolation, async/await, or Task creation does not by itself prove background-thread execution; Sendable conformance alone does not prove thread-safe mutation.

@MainActor/MainActor.run, DispatchQueue.main, and RunLoop.main are reported as distinct isolation, queue, and event-loop mechanisms. A plain Task is kept separate from Task.detached; neither is labeled as a background thread.

Reference code

RealityKitAnimation/Packages/RealityKitContent/Sources/RealityKitContent/EntityMoverComponent.swift:28 — representative execution boundary

@MainActor
public struct EntityMoverRuntimeComponent: Component {
    // ...
    private var settingsSource: EntityMoverComponent? = nil
    // ...
}

State propagation, frameworks, and dependencies

Evidence limit: an import proves a source-level compilation dependency at the cited line; it does not prove runtime use, architectural adoption, or whether a Swift package is a direct application dependency.

receive(on:) describes downstream delivery scheduling, while subscribe(on:) describes upstream subscription/request/cancel scheduling. An import Combine alone establishes neither behavior nor a Store, reducer, Redux, or other application architecture.

Class and protocol design

RealityKitAnimation/RealityKitAnimation/RealityKitAnimationApp.swift:11 — representative type boundary

@main
struct RealityKitAnimationApp: App {
    // ...
    @State private var appModel = AppModel()
    // ...
}

No local protocol conformance is claimed as protocol-oriented design; external framework conformances are listed only as dependencies.

Access control

Reference code

RealityKitAnimation/Packages/RealityKitContent/Sources/RealityKitContent/EntityMoverComponent.swift:31 — representative boundary

@MainActor
public struct EntityMoverRuntimeComponent: Component {
    // ...
    private var settingsSource: EntityMoverComponent? = nil
    // ...
}

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Design patterns

Naming conventions

• Types: App: RealityKitAnimationApp; Component: EntityMoverComponent, EntityMoverRuntimeComponent, HeroPlantComponent, HeroPlantRuntimeComponent, HeroRobotComponent; Model: AppModel; System: EntityMoverSystem, HeroPlantSystem, HeroRobotSystem, StationaryRobotSystem; View: ContentView, ImmersiveView.
• Protocols: no local protocol declaration in the scanned source.
• Methods: isAvailable, setState, enableIK, calculateReachPosition, initialize, initializeIKComponent, initializeRobotTravelHomeAction, findModelComponentEntity.
• Files: RealityKitAnimation/RealityKitAnimation/RealityKitAnimationApp.swift, RealityKitAnimation/Packages/RealityKitContent/Sources/RealityKitContent/HeroRobotComponent.swift, RealityKitAnimation/Packages/RealityKitContent/Sources/RealityKitContent/HeroPlantComponent.swift, RealityKitAnimation/Packages/RealityKitContent/Sources/RealityKitContent/EntityMoverComponent.swift, RealityKitAnimation/Packages/RealityKitContent/Sources/RealityKitContent/StationaryRobotComponent.swift, RealityKitAnimation/RealityKitAnimation/AppModel.swift.

Architecture takeaways

• RealityKitAnimationApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches RealityKit, SwiftUI, Spatial, RealityKitContent through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
• Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
• Access-control conclusions separate verified language visibility from the likely design rationale.
• The source does not justify labeling the design protocol-oriented.

Source map

• Official Apple documentation