Scanning and Detecting 3D Objects

At a glance

Project structure

Source bundle/
└── ScanningApp/
    ├── Controllers/
    │   ├── AppDelegate.swift
    │   ├── ShareScanViewController.swift
    │   ├── ViewController.swift
    │   ├── Scan.swift
    │   ├── TestRun.swift
    │   ├── ViewController+ApplicationState.swift
    │   ├── ViewController+Gestures.swift
    │   └── ViewController+NavigationBar.swift
    ├── Utility Extensions/
    │   └── Utilities.swift
    ├── 3D UI and Visualizations /
    │   ├── BoundingBox.swift
    │   └── BoundingBoxSide.swift
    └── Views/
        └── MessageLabel.swift

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Metal, Swift.
• The verified tree contains 6 project/configuration file(s) and 31 source declaration(s).

Overall architecture

flowchart LR
    N1["AppDelegate"]
    N2["ShareScanViewController"]
    N3["ARKit APIs"]
    N1 --> N2
    N2 --> N3

Reference code

ScanningApp/Controllers/AppDelegate.swift:11 — architecture anchor

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    // ...
    var window: UIWindow?
    // ...
}

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 ARKit.

Ownership and state

classDiagram
    BoundingBox o-- Notification : extentChangedNotification
    BoundingBox o-- Notification : positionChangedNotification
    BoundingBox o-- Notification : scanPercentageChangedNotification
    BoundingBox o-- Extent : extent

Ownership evidence

ScanningApp/3D UI and Visualizations /BoundingBox.swift:13 — stored dependency or nearest verified ownership anchor

class BoundingBox: SCNNode {
    // ...
    static let extentChangedNotification = Notification.Name("BoundingBoxExtentChanged")
    // ...
}

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

ScanningApp/Controllers/ViewController+ApplicationState.swift:133 — representative execution boundary

        DispatchQueue.main.async {
            // ...
            case .ready:
            // ...
        }

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

ScanningApp/3D UI and Visualizations /PointCloud+CreateVisualization.swift:11 — representative type boundary

protocol PointCloud {
    func createVisualization(for points: [SIMD3<Float>], color: UIColor, size: CGFloat) -> SCNGeometry?
}

The source explicitly defines local protocol relationships: DetectedPointCloud → PointCloud, ScannedPointCloud → PointCloud.

Access control

Reference code

ScanningApp/3D UI and Visualizations /BoundingBox.swift:38 — representative boundary

class BoundingBox: SCNNode {
    // ...
    private var maxDistanceToFocusPoint: Float = 0.05
    // ...
}

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: Controller: ShareScanViewController, ViewController; Delegate: AppDelegate.
• Protocols: PointCloud.
• Methods: application, applicationWillEnterForeground, applicationWillResignActive, applicationDidBecomeActive, viewWillAppear, viewWillDisappear, viewDidLoad, viewDidLayoutSubviews.
• Files: ScanningApp/Controllers/AppDelegate.swift, ScanningApp/Controllers/ShareScanViewController.swift, ScanningApp/Controllers/ViewController.swift, ScanningApp/Controllers/Scan.swift, ScanningApp/Controllers/TestRun.swift, ScanningApp/3D UI and Visualizations /BoundingBox.swift.

Architecture takeaways

• AppDelegate is the main source-visible entry or composition anchor for this sample.
• Framework work reaches ARKit, UIKit, SceneKit, AVFoundation 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.
• Local protocol relationships provide an explicit substitution boundary.

Source map

• Official Apple documentation