DontDestroyOnLoad usage in Unity - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does DontDestroyOnLoad do in Unity?

DontDestroyOnLoad keeps a GameObject alive when loading a new scene. It prevents the object from being destroyed.

beginner

How do you use DontDestroyOnLoad in a script?

Call DontDestroyOnLoad(gameObject); inside a script, usually in Awake() or Start() method.

beginner

Why would you use DontDestroyOnLoad for a GameObject?

To keep important objects like managers, audio players, or player data alive across multiple scenes.

intermediate

What happens if you use DontDestroyOnLoad on multiple instances of the same GameObject?

You may end up with duplicates in your game. Usually, you want to check and keep only one instance.

intermediate

Can DontDestroyOnLoad be used on child GameObjects?

Yes, it can be used on child GameObjects. It preserves the child and its descendants, detaching it from the parent if the parent is destroyed.

What is the main purpose of DontDestroyOnLoad in Unity?

A Keep a GameObject alive between scene loads

B Destroy a GameObject immediately

C Load a new scene asynchronously

D Reset a GameObject's position

DontDestroyOnLoad keeps the GameObject alive when switching scenes.

Where is the best place to call DontDestroyOnLoad(gameObject); in a script?

A Inside <code>Awake()</code> or <code>Start()</code>

B Inside <code>Update()</code>

C Inside <code>OnDestroy()</code>

D Inside <code>OnEnable()</code>

Calling it in Awake() or Start() ensures the object is preserved early.

What problem can happen if you don't manage multiple instances of a DontDestroyOnLoad object?

A The scene fails to load

B Multiple duplicates of the object appear

C The object is destroyed immediately

D The object loses its components

Without checks, duplicates accumulate, causing bugs or performance issues.

Can DontDestroyOnLoad be applied to a child GameObject directly?

A Only if the child is active

B Only if the child has a Rigidbody

C Yes, any GameObject can be preserved

D No, only root GameObjects can be preserved

DontDestroyOnLoad works on any GameObject, including children. The child and its subtree are preserved and become roots in the DontDestroyOnLoad scene.

Which of these is a common use case for DontDestroyOnLoad?

A Changing scene lighting settings

B Resetting player position on scene load

C Destroying enemies when a scene loads

D Keeping a music player alive across scenes

Music players or managers often use DontDestroyOnLoad to continue playing music seamlessly.

Explain how and why you would use DontDestroyOnLoad in a Unity project.

Think about objects that should not reset when changing scenes.

Describe a potential problem when using DontDestroyOnLoad without proper management and how to fix it.

Consider what happens if multiple scenes create the same persistent object.