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name: Unity UI System Selector description: Guides selection between UGUI and UI Toolkit for projects. Use when choosing UI framework or migrating UI systems.

Unity UI System Selector

Helps you choose the appropriate UI system for your Unity project and provides implementation guidance for both UGUI and UI Toolkit.

Two UI Systems

UGUI (Legacy) - GameObject-based (2014). Mature, works on all Unity versions, large community. Weaker: Complex UI performance, limited styling, no live reload.

UI Toolkit (Modern) - Retained mode, web-inspired UXML/USS (2021.2+). Better performance, live reload, data-binding. Weaker: Requires 2021.2+, smaller community, limited 3D world-space UI.

Decision Framework

Use UGUI if:

• Unity < 2021.2
• Simple UI (menus, HUD)
• 3D world-space UI needed
• Team knows UGUI well / tight deadline
• Legacy project

Use UI Toolkit if:

• Unity 2021.2+ and new project (future-proof)
• Complex/data-driven UI (inventory, skill trees)
• Editor tools (inspectors, windows) - strongly recommended
• Web dev background (HTML/CSS)
• Large-scale UI (MMO, strategy games)

When in doubt: For new projects on Unity 2021.2+, UI Toolkit is recommended.

Comparison

Feature	UGUI	UI Toolkit
Version	4.6+	2021.2+
Performance	Simple UIs	All UIs
Styling	Inspector	CSS-like USS
Layout	Manual/Groups	Flexbox-like
Editor Tools	Good	Excellent
Runtime UI	Excellent	Good
3D World UI	Excellent	Limited

Migration

See migration-guide.md for UGUI → UI Toolkit migration strategy (3-4 months for medium projects).

UI System Support Matrix

Unity Version	UGUI	UI Toolkit (Editor)	UI Toolkit (Runtime)
2019.4 LTS	✅ Full	✅ Basic	❌ No
2020.3 LTS	✅ Full	✅ Good	⚠️ Experimental
2021.3 LTS	✅ Full	✅ Excellent	✅ Production
2022.3 LTS+	✅ Full	✅ Primary	✅ Full

When to Use vs Other Components

Use this Skill when: Choosing between UGUI and UI Toolkit, understanding UI system trade-offs, or planning UI migration

Use @unity-scripter agent when: Implementing UI components, writing custom UI scripts, or converting UI code

Use @unity-architect agent when: Designing complex UI architecture, planning UI data flow, or structuring large-scale UI systems

Use /unity:new-script command when: Generating Editor scripts with UI Toolkit or UGUI templates

Related Skills

• unity-uitoolkit: Assists with UI Toolkit implementation (UXML, USS, VisualElement API)
• unity-template-generator: Generates Editor scripts using selected UI system
• unity-script-validator: Validates UI code patterns