The Missing Manual
⌘K
All topics / Unity From Zero

Unity From Zero

Learn the game engine behind a huge share of the games industry: the editor, GameObjects and Components, the MonoBehaviour script lifecycle, transforms and input and movement, physics and collisions, prefabs and instantiation, UI and audio, and building your game. C# game development, taught mental-model-first.

  1. What Unity Is Unity is a game engine plus editor: it handles rendering, physics, audio, input, and builds, while you supply assets and C# scripts. Its core idea is composition — scenes hold GameObjects, GameObjects hold Components.
  2. The Editor Tour the Unity editor: the Hierarchy, Scene, Game, Inspector, Project, and Console windows, how Play mode works, the edits-during-Play trap, and building the first scene of your game.
  3. GameObjects & Components The core Unity pattern: a GameObject is an empty bag of Components. The Transform is always there; looks, physics, and behavior are Components you attach — composition over inheritance.
  4. MonoBehaviour & the Game Loop How a C# script becomes a Component the engine drives: the MonoBehaviour lifecycle, Start vs Update, frame-rate-independent movement with Time.deltaTime, and Inspector-tweakable fields.
  5. Transforms, Input & Movement Move a GameObject by changing its Transform every frame, scaled by Time.deltaTime and driven by input. Vector3, transform.position, Input.GetAxis, the modern Input System, and a real PlayerMovement script.
  6. Physics & Collisions Hand an object to the physics engine with a Rigidbody, give it shape with Colliders, and react to contact with OnCollisionEnter and OnTriggerEnter — the right way to move characters and collect pickups.
  7. Prefabs & Instantiation Prefabs are reusable GameObject templates: edit once, every copy updates. Spawn them at runtime with Instantiate, remove them with Destroy, and meet object pooling for spawn-heavy games.
  8. UI, Audio & Building Turn the pickups demo into a real game: a Canvas with TextMeshPro score text, a GameManager holding shared state, an AudioSource for pickup sounds and music, then a build that exports your scenes to a platform.
  9. Where to Go Next You built a real game in Unity. Now: how Unity compares to Godot and Unreal, the engine features to learn next, the truth that gamedev is more than code, and what to build.