// Project Cleanup Utility — main application window

Project Cleanup Utility is a Level 5 solo module project (GDEV50047) at Staffordshire University — a fully featured Unity 6 Editor tool for scanning, categorising, quarantining, and managing unused and duplicate assets in Unity projects. It was built entirely using the Unity Editor API and UI Toolkit, with no external dependencies or native plugins.

The tool was chosen over two other pitched alternatives (an FFmpeg video encoder and a ScriptableObject database editor) because it solves a well-documented, industry-wide pain point: Unity imports and indexes every file in the Assets folder regardless of use, silently accumulating dead weight across editor performance, version control storage, CI/CD pipelines, and developer cognitive load. No first-party Unity tool exists for this.

Development followed an iterative and incremental approach — scanning first, then quarantine, then dependency graph, then exports, then accessibility — each increment building on a working, tested foundation.

The tool is structured across four layers — each with a single, clear responsibility. The UI layer never touches file I/O. The core layer never renders anything. Data models are plain serialisable objects with no Unity coupling. This separation made incremental development straightforward: each increment added a new layer without touching the others.

// Asset scanner — scanning in progress

AssetScanner.cs (696 lines) is the engine of the tool. It walks every asset in the project via AssetDatabase.GetAllAssetPaths, builds a reverse-dependency map using AssetDatabase.GetDependencies, then classifies each asset's deletion safety. A progress callback fires for every asset so the UI stays live during long scans.

The scanner accounts for string-based asset references — Resources.Load paths, Addressables keys, and serialised string fields in C# — using pre-compiled regex patterns, so assets only referenced by name rather than serialised GUID are not incorrectly flagged as unused.

Deletion safety is computed from the reverse-dependency graph:

Content-hash duplicate detection groups assets by SHA-256 file content hash. Any group with two or more members is surfaced in the Overview panel with total wasted size. In a live TankController project scan: 219 hash groups, 440 duplicate files, 14.13 MB wasted.

The final development iteration was dedicated entirely to accessibility — a deliberate choice to ensure the tool shipped usable, not just functional. The implementation is informed by WCAG 2.1 Perceivable, Operable, and Understandable principles, and the Microsoft Inclusive Design methodology.

transform.scale breaking layout — The first UI Scale implementation set rootVisualElement.transform.scale to a Vector3 scalar. UI Toolkit's layout pass runs before the render transform, so at any scale other than 1.0, the visual content and layout bounds diverge — content clips off the bottom of the window. Fixed by abandoning transform.scale entirely and folding the scale factor into the base font size via ApplyFontSize().

Safety label colours not updating in colour-blind mode — The Safety column bindCell callback was setting label.style.color directly in C# — three separate hardcoded RGBA values. Inline styles override all USS rules regardless of specificity. Fixed by removing all inline colour from C# and using USS safety classes (safety-safe, safety-caution, safety-unsafe) managed by the bindCell callback.

:focus-within row highlight failing — A focused-row USS rule using :focus-within caused silent console warnings in Unity's UI Toolkit. USS does not support the :focus-within pseudo-class in the Unity runtime. The row highlight was dropped; the per-control :focus indicator was retained as a functional compromise.