DontDestroyOnLoad usage in Unity - Step-by-Step Execution

Concept Flow - DontDestroyOnLoad usage

Start Scene

↓

Create GameObject

↓

Call DontDestroyOnLoad

↓

Load New Scene

↓

GameObject persists

↓

Continue Game with same GameObject

This flow shows how a GameObject is created, marked to not be destroyed, and then persists across scene loads.

Execution Sample

Unity

void Awake() {
  DontDestroyOnLoad(gameObject);
}

// Load new scene later

This code marks the GameObject to persist when a new scene loads.

Execution Table

Step	Action	GameObject State	Scene Loaded	Result
1	GameObject created in Scene 1	Exists in Scene 1	Scene 1	GameObject active
2	DontDestroyOnLoad called on GameObject	Marked to persist	Scene 1	GameObject will not be destroyed on scene load
3	Load Scene 2	Still exists	Scene 2	GameObject persists across scenes
4	Game continues in Scene 2	Exists in Scene 2	Scene 2	GameObject usable in new scene
5	Load Scene 3	Still exists	Scene 3	GameObject persists again
6	End	GameObject still alive	Scene 3	Execution stops

💡 Execution stops after GameObject persists through scene loads

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 5	Final
gameObject	Created in Scene 1	Marked DontDestroyOnLoad	Exists in Scene 2	Exists in Scene 3	Still exists

Key Moments - 3 Insights

Why doesn't the GameObject get destroyed when a new scene loads?

Because DontDestroyOnLoad was called on the GameObject (see Step 2 in execution_table), it is marked to persist and Unity keeps it alive across scene loads.

Does DontDestroyOnLoad prevent the GameObject from being destroyed manually?

No, DontDestroyOnLoad only prevents destruction during scene loads. The GameObject can still be destroyed by code or user actions.

What happens if you call DontDestroyOnLoad on multiple GameObjects?

Each marked GameObject will persist across scenes independently, allowing you to keep multiple objects alive (not shown in this trace but same principle applies).

Visual Quiz - 3 Questions

Look at the execution_table, at which step is DontDestroyOnLoad called on the GameObject?

A Step 3

B Step 2

C Step 1

D Step 4

💡 Hint

Check the 'Action' column in execution_table for when DontDestroyOnLoad is called

According to variable_tracker, what is the state of the GameObject after loading Scene 3?

A Exists in Scene 3

B Marked DontDestroyOnLoad but destroyed

C Destroyed

D Not created yet

💡 Hint

Look at the 'After Step 5' column for gameObject in variable_tracker

If DontDestroyOnLoad was not called, what would happen at Step 3 when loading Scene 2?

A GameObject would persist

B Scene would not load

C GameObject would be destroyed

D GameObject would duplicate

💡 Hint

Recall that without DontDestroyOnLoad, GameObjects in the old scene are destroyed on scene load

Concept Snapshot

DontDestroyOnLoad usage in Unity:
- Call DontDestroyOnLoad(gameObject) in Awake or Start
- Marks GameObject to persist across scene loads
- Prevents destruction only during scene changes
- Useful for managers, audio, or player objects
- GameObject remains active and usable in new scenes

Full Transcript

This visual execution trace shows how DontDestroyOnLoad works in Unity. First, a GameObject is created in the starting scene. Then, DontDestroyOnLoad is called on it, marking it to persist. When a new scene loads, normally all objects are destroyed, but this GameObject stays alive. It continues to exist and be usable in the new scene. The variable tracker confirms the GameObject's state after each step. Key points include that DontDestroyOnLoad only prevents destruction during scene loads, not manual destruction. The quiz questions help reinforce understanding of when and why the GameObject persists.