Manipulating models with RealityKit

At a glance

Project structure

Source bundle/
└── ModelManipulator/
    ├── ModelManipulatorApp.swift
    ├── Models/
    │   ├── AppModel.swift
    │   ├── ClippingController.swift
    │   └── ClippingPlane.swift
    ├── Components/
    │   ├── ClippingBoundsCacheComponent.swift
    │   └── ClippingTransformSyncComponent.swift
    ├── Scenes/
    │   └── ImmersiveScene.swift
    ├── Systems/
    │   └── ClippingTransformSyncSystem.swift
    └── Views/
        ├── ContentView.swift
        ├── EntityHierarchyView.swift
        ├── ImmersiveControlsView.swift
        └── ImmersiveView.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 29 source declaration(s).

Overall architecture

flowchart LR
    N1["ModelManipulatorApp"]
    N2["ClippingController"]
    N3["AppModel"]
    N4["ClippingTransformSyncSystem"]
    N5["RealityKit APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4
    N4 --> N5

Reference code

ModelManipulator/ModelManipulatorApp.swift:10 — architecture anchor

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

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
    ModelManipulatorApp *-- AppModel : appModel
    AppModel o-- Entity : modelEntity
    AppModel *-- URL : selectedModelURL
    AppModel *-- Dictionary : clippingControllers

Ownership evidence

ModelManipulator/ModelManipulatorApp.swift:12 — stored dependency or nearest verified ownership anchor

@main
struct ModelManipulatorApp: 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

ModelManipulator/Entities/ClippingControlEntity.swift:21 — representative execution boundary

    static func makeEntity() async throws -> ClippingControlEntity {
        let entity = ClippingControlEntity()
        // ...
    }

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

ModelManipulator/ModelManipulatorApp.swift:11 — representative type boundary

@main
struct ModelManipulatorApp: 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

ModelManipulator/Entities/ClippingControlEntity.swift:13 — representative boundary

final class ClippingControlEntity: Entity {
    private weak var clippedEntity: Entity?
    // ...
}

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: ModelManipulatorApp; Component: ClippingBoundsCacheComponent, ClippingTransformSyncComponent; Controller: ClippingController; Model: AppModel; Scene: ImmersiveScene; System: ClippingTransformSyncSystem; View: ContentView, EntityHierarchyView, ImmersiveControlsView, ImmersiveView.
• Protocols: no local protocol declaration in the scanned source.
• Methods: enterImmersivePresentation, exitImmersivePresentation, makeDefaultScenes, handleClippingStateChange, presentFileImporter, reset, selectDefaultModel, selectModel.
• Files: ModelManipulator/ModelManipulatorApp.swift, ModelManipulator/Models/AppModel.swift, ModelManipulator/Models/ClippingController.swift, ModelManipulator/Components/ClippingBoundsCacheComponent.swift, ModelManipulator/Components/ClippingTransformSyncComponent.swift, ModelManipulator/Scenes/ImmersiveScene.swift.

Architecture takeaways

• ModelManipulatorApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, RealityKit, simd, UniformTypeIdentifiers 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