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GameObject

Type	Class (sealed)
Namespace	`UnityEngine`
Inherits	Object
In scripts	`gameObject` (the one your script is on)

GameObject

A GameObject is any object in your scene. On its own it's an empty container with a name and a Transform. You make it do things by adding components.

Inside a MonoBehaviour, gameObject (lowercase) is the GameObject the script is attached to. GameObject (uppercase) is the class, used for static functions like GameObject.Find.

Properties

SetActive(false) is unplugging an appliance. It's still in the room (in the Hierarchy), keeps its settings, and you can plug it back in anytime. Unplugging a power strip (a parent) turns off everything plugged into it (the children), even if each device's own switch (activeSelf) is still on.

Name	Type	Description
`name`	`string`	Name shown in the Hierarchy.
`transform`	`Transform`	Its position, rotation and scale. Every GameObject has one.
`activeSelf`	`bool`	Is this object's own checkbox ticked? (Read only. Use `SetActive` to change.)
`activeInHierarchy`	`bool`	Is it actually active? False if it or any parent is inactive.
`tag`	`string`	A label like "Player" or "Enemy". Add tags in the Tags & Layers settings.
`layer`	`int`	Layer number (0-31). Used for physics filtering and camera culling.
`scene`	`Scene`	The scene it belongs to.

Methods

Method	Returns	Description
`SetActive(bool value)`	`void`	Turns the object (and all its children) on or off. Off means no rendering, no physics, no `Update`.
`GetComponent<T>()`	`T`	Gets a component of type `T` on this object, or `null` if there isn't one.
`TryGetComponent<T>(out T component)`	`bool`	Like `GetComponent` but returns `true`/`false`. Cleaner when the component might be missing.
`GetComponentInChildren<T>()`	`T`	Searches this object, then its children (depth-first).
`GetComponentInParent<T>()`	`T`	Searches this object, then its parents.
`GetComponents<T>()`	`T[]`	All components of type `T` on this object.
`AddComponent<T>()`	`T`	Adds a new component and returns it. Its `Awake` runs immediately.
`CompareTag(string tag)`	`bool`	Checks the tag. Faster than `tag == "Player"`.

Static Methods

Method	Returns	Description
`GameObject.Find(string name)`	`GameObject`	Finds an active object by name. Slow; avoid in `Update`.
`GameObject.FindWithTag(string tag)`	`GameObject`	Finds one active object with the tag.
`GameObject.FindGameObjectsWithTag(string tag)`	`GameObject[]`	Finds all active objects with the tag.
`GameObject.CreatePrimitive(PrimitiveType type)`	`GameObject`	Creates a cube, sphere, capsule, etc. with mesh and collider.

For Instantiate, Destroy and DontDestroyOnLoad, see Object.

Code Samples

Getting components safely

using UnityEngine;

public class Damager : MonoBehaviour
{
    void OnTriggerEnter(Collider other)
    {
        // Does the thing we hit have a Health script?
        if (other.TryGetComponent<Health>(out Health health))
        {
            health.TakeDamage(10);
        }
    }
}

Showing and hiding a menu

using UnityEngine;

public class PauseMenu : MonoBehaviour
{
    [SerializeField] private GameObject menuPanel; // drag the menu UI object here

    void Update()
    {
        if (Input.GetKeyDown(KeyCode.Escape))
        {
            bool show = !menuPanel.activeSelf;
            menuPanel.SetActive(show);
            Time.timeScale = show ? 0f : 1f; // freeze the game while the menu is open
        }
    }
}

Building an object entirely from code

GameObject go = new GameObject("Enemy");  // an empty GameObject with only a Transform
go.transform.position = new Vector3(0f, 1f, 5f);
go.AddComponent<Rigidbody>();
go.AddComponent<BoxCollider>();
go.tag = "Enemy"; // the tag must already exist in Tags & Layers

What happens at runtime

SetActive(false)

OnDisable is called on every script on the object and on all its children.
The object stops rendering, its colliders are removed from physics, and Update / FixedUpdate stop being called.
Coroutines running on its scripts are stopped (and won't resume when reactivated).
Children keep their own activeSelf value, but their activeInHierarchy becomes false.

SetActive(true)

OnEnable is called on enabled scripts. If a script's Awake has never run (object started inactive), it runs now, followed later by Start.

Common Mistakes

GameObject.Find can't find inactive objects. Keep a reference in a serialized field instead.
Calling Find or GetComponent every frame. Cache the result in Awake or Start.
Comparing tags with ==. Works, but CompareTag is faster and doesn't allocate memory.
Checking activeSelf when you mean "is it visible". A child can be activeSelf == true but hidden because its parent is off. Use activeInHierarchy.

GameObject

Properties

Methods

Static Methods

Code Samples

Getting components safely

Showing and hiding a menu

Building an object entirely from code

What happens at runtime

Common Mistakes

See also