Unity Simple Docs

A beginner-friendly rewrite of the Unity documentation. Every page explains what an API does, shows how to use it with a working example, and describes what actually happens while your game is running.

Which Unity version?

Examples target Unity 6 and use C#. The pages assume you know basic C# (variables, methods, classes, if statements) but are new to Unity. Most of it also works in Unity 2021 and 2022. When a name changed in Unity 6 (for example Rigidbody.velocity became Rigidbody.linearVelocity), the page says so.

New to Unity? Start here

Read these in order. Each one builds on the last.

1. What is Unity?: GameObjects, Components, Scenes and the Editor windows
2. Your First Script: write a C# script and attach it to an object
3. Script Lifecycle: when Unity calls Awake, Start, Update and the others
4. Prefabs & Spawning: reusable objects and Instantiate
5. Coroutines: waiting and doing things over time
6. Physics Basics: Rigidbodies, Colliders and triggers
7. Handling Input: keyboard, mouse and gamepad

C# for Unity

The C# language features you'll meet in Unity code, each explained with Unity examples.

Also: Fields, Properties & Modifiers, Inheritance & Interfaces, Null, Generics, Collections, LINQ, Enums, Strings, Extension Methods, Attributes.

Tutorials

Step-by-step builds of real game features. Each one ends with something you can play.

HLSL & Shaders

Guides

• Procedural Meshes without GameObjects: build a shape in code and draw many copies without GameObjects
• Dot, Cross & Reflect: "is it in front of me?", "which way is sideways?" and "which way does it bounce?"
• Working with CharacterController: walk, jump and bump into walls with full control over the feel
• URP & Post-processing: glow, colour grading and screen effects with Volumes
• UI & TextMeshPro in Depth: menus, health bars and text that fit any screen size
• NavMesh in Depth: let characters find their own way around walls
• Working with Particle Systems: explosions, dust, rain, and controlling effects from code
• Working with Update & FixedUpdate: the two game loops, what goes where, and how to fix jitter
• Interpolation & Easing: Lerp, MoveTowards, SmoothDamp, and making motion feel good
• Bezier Curves: arcs and paths, moving along a curve at constant speed
• Better Ways to Do Things: beginner habits that cause trouble later, and what to do instead

Building Systems

• Building Your Own Systems: design small reusable systems, with your own object pool and cooldown timer
• Simple State Machines: patrol, chase and attack without a mess of if statements
• Saving & Loading Games: save progress to a JSON file and load it back

Performance

• Optimization Best Practices: budgets, profiling on real devices, CPU vs GPU, engine and asset settings
• Optimizing Your Code: caching, garbage, cheaper math and other script-level tips
• Object Pooling: reuse bullets, effects and enemies instead of creating and destroying them
• GPU Instancing & Batching: draw thousands of objects with a handful of draw calls

API Reference

See the sidebar for the full list.

How to read an API page

API pages follow the same layout so you always know where to look:

• Infobox (top right): what kind of type it is, what it inherits from, and which namespace to put in your using line.
• Summary: what it is, in one or two plain sentences.
• Think of it like...: a real-world comparison for the trickier ideas, shown in a purple box.
• Properties / Methods / Events: tables of the members you will actually use. Rarely used members are left out.
• Diagrams: where a picture explains the mechanism faster than words (timelines, flows, geometry). On a phone, swipe sideways on a wide diagram.
• Code Samples: complete scripts you can copy into a project.
• What happens at runtime: what Unity does behind the scenes, step by step.
• Common Mistakes: the things that trip most beginners up.