Build settings and scene order in Unity - Step-by-Step Execution

Concept Flow - Build settings and scene order

Open Build Settings

↓

Add Scenes to Build

↓

Arrange Scene Order

↓

Set First Scene as Entry

↓

Build and Run Game

↓

Game Starts

This flow shows how you open build settings, add scenes, arrange their order, set the first scene, and then build and run the game.

Execution Sample

Unity

// Pseudocode for setting build scenes order
var buildScenes = new List<Scene>()
buildScenes.Add(scene1)
buildScenes.Add(scene2)
// scene1 is first, scene2 second
BuildPlayer(buildScenes);

This code adds scenes to the build list in order and builds the player with that order.

Execution Table

Step	Action	Scene List Order	First Scene (Entry Point)	Result
1	Open Build Settings window	[]	None	Build Settings window opens
2	Add Scene1 to build	[Scene1]	Scene1	Scene1 added, becomes first scene
3	Add Scene2 to build	[Scene1, Scene2]	Scene1	Scene2 added after Scene1
4	Rearrange scenes: move Scene2 up	[Scene2, Scene1]	Scene2	Scene2 is now first scene
5	Build and run game	[Scene2, Scene1]	Scene2	Game starts with Scene2
6	Exit	[Scene2, Scene1]	Scene2	Build complete, game launched

💡 Build and run completes, game starts with first scene in list

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	Final
Scene List	[]	[Scene1]	[Scene1, Scene2]	[Scene2, Scene1]	[Scene2, Scene1]
First Scene	None	Scene1	Scene1	Scene2	Scene2

Key Moments - 3 Insights

Why does the first scene in the list become the entry point of the game?

Because Unity always starts the game with the first scene listed in Build Settings, as shown in steps 2 and 4 where changing order changes the entry scene.

What happens if you add scenes but don't arrange their order?

The scenes run in the order they were added, so the first added scene is the entry point, as seen in steps 2 and 3.

Can you start the game with a scene not in the build list?

No, only scenes included in the build settings list can be used to start the game, otherwise the build will fail or skip that scene.

Visual Quiz - 3 Questions

Look at the execution table, which scene is the entry point after step 4?

A Scene2

B Scene1

C No scene

D Both scenes

💡 Hint

Check the 'First Scene (Entry Point)' column at step 4 in the execution table.

At which step does Scene2 get added to the build list?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Look at the 'Action' column for when Scene2 is added in the execution table.

If you remove Scene1 after step 3, what will be the first scene?

A Scene1

B Scene2

C No scene

D Scene3

💡 Hint

Refer to the variable_tracker for scene list changes and first scene after removing Scene1.

Concept Snapshot

Build Settings and Scene Order in Unity:
- Open Build Settings window
- Add scenes to the build list
- Arrange scenes to set game start order
- First scene in list is entry point
- Build and run starts game from first scene

Full Transcript

In Unity, you open the Build Settings window to manage which scenes are included in your game build. You add scenes to the build list, and the order of these scenes determines which scene starts first when the game runs. The first scene in the list is the entry point. You can rearrange scenes to change the starting scene. After setting the scenes and order, you build and run the game, which launches starting from the first scene in the list.

Practice

1. What does the Build Settings window in Unity control?

easy

A. Which scenes are included in the final game build

B. The resolution of the game window

C. The color scheme of the editor

D. The physics settings of the game

Solution

1. Step 1: Understand the purpose of Build Settings

   The Build Settings window lists scenes to include in the game build and their order.

2. Step 2: Identify what Build Settings controls

   It controls which scenes are packaged into the final game, not editor or physics settings.

3. Final Answer:

   Which scenes are included in the final game build -> Option A

4. Quick Check:

   Build Settings = Scenes included [OK]

Hint: Build Settings = scenes included in game build [OK]

Common Mistakes:

• Confusing Build Settings with editor appearance
• Thinking it controls physics or resolution
• Assuming it sets scene start order only

2. Which of the following is the correct way to add a scene to the build in Unity?

easy

A. Drag the scene file into the Build Settings window's Scenes In Build list

B. Right-click the scene in Project and select 'Add to Build'

C. Open the scene and press Ctrl+B

D. Rename the scene file to include 'build' in its name

Solution

1. Step 1: Recall how to add scenes to build

   In Unity, you add scenes by dragging them into the Scenes In Build list in Build Settings.

2. Step 2: Evaluate the options

   Only dragging the scene file into Build Settings is correct; other options are invalid or do nothing.

3. Final Answer:

   Drag the scene file into the Build Settings window's Scenes In Build list -> Option A

4. Quick Check:

   Add scene = drag to Build Settings [OK]

Hint: Add scenes by dragging into Build Settings list [OK]

Common Mistakes:

• Trying to add scenes by renaming files
• Using keyboard shortcuts that don't add scenes
• Expecting context menu to add scenes automatically

3. Given the following scenes in Build Settings in order: ["Menu", "Level1", "Level2"], what will SceneManager.LoadScene(1) load?

medium

A. The scene named "Menu"

B. The scene named "Level1"

C. The scene named "Level2"

D. An error because index 1 is invalid

Solution

1. Step 1: Understand scene indexing in Build Settings

   Scenes are indexed starting at 0 in the order listed in Build Settings.

2. Step 2: Identify scene at index 1

   Index 0 = "Menu", index 1 = "Level1", index 2 = "Level2".

3. Final Answer:

   The scene named "Level1" -> Option B

4. Quick Check:

   Index 1 = second scene = Level1 [OK]

Hint: Scene index starts at 0 in Build Settings [OK]

Common Mistakes:

• Assuming index 1 is the first scene
• Confusing scene names with indexes
• Thinking index 1 causes an error

4. You try to load a scene by index using SceneManager.LoadScene(3), but get an error. What is the most likely cause?

medium

A. SceneManager.LoadScene only accepts strings

B. You must use scene names, not indexes

C. The scene file is missing from the Project folder

D. The scene at index 3 is not added to Build Settings

Solution

1. Step 1: Understand scene indexing and Build Settings

   Scene indexes correspond to the order in Build Settings; index 3 means the fourth scene.

2. Step 2: Identify cause of error

   If index 3 is out of range, it means fewer than 4 scenes are added to Build Settings.

3. Final Answer:

   The scene at index 3 is not added to Build Settings -> Option D

4. Quick Check:

   Index out of range = scene missing in Build Settings [OK]

Hint: Check Build Settings scene count before loading by index [OK]

Common Mistakes:

• Thinking indexes are unrelated to Build Settings
• Believing LoadScene only accepts names
• Assuming missing file causes this specific error

5. You want your game to start with the "Intro" scene, but currently the "MainMenu" scene is first in Build Settings. How can you fix this without renaming scenes?

hard

A. Call SceneManager.LoadScene("Intro") in the first scene's script

B. Change the scene file name to "00_Intro"

C. Drag the "Intro" scene to the top of the Scenes In Build list

D. Remove "MainMenu" from Build Settings

Solution

1. Step 1: Understand scene start order in Build Settings

   The first scene in the Scenes In Build list is the one that starts when the game runs.

2. Step 2: Adjust scene order without renaming

   Drag the "Intro" scene to the top of the list to make it the first scene loaded.

3. Final Answer:

   Drag the "Intro" scene to the top of the Scenes In Build list -> Option C

4. Quick Check:

   First scene in Build Settings = start scene [OK]

Hint: First scene in Build Settings list starts game [OK]

Common Mistakes:

• Renaming files instead of reordering scenes
• Removing scenes unnecessarily
• Relying only on script calls without build order