Scene creation and management in Unity - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Unity C# code when loading a scene?

Consider the following Unity C# script snippet that loads a scene asynchronously:

using UnityEngine;
using UnityEngine.SceneManagement;

public class SceneLoader : MonoBehaviour {
    void Start() {
        SceneManager.LoadSceneAsync("Level2");
        Debug.Log("Scene loading started");
    }
}

What will be printed in the Unity Console when this script runs?

Unity

using UnityEngine;
using UnityEngine.SceneManagement;

public class SceneLoader : MonoBehaviour {
    void Start() {
        SceneManager.LoadSceneAsync("Level2");
        Debug.Log("Scene loading started");
    }
}

A No output because LoadSceneAsync is asynchronous

B Scene loading started\nLevel2 scene loaded

C Scene loading started

D Error: Scene 'Level2' not found

💡 Hint

Remember that LoadSceneAsync starts loading but does not block the thread.

The Debug.Log runs immediately after starting the asynchronous load, so only "Scene loading started" is printed at that moment. The actual scene load completes later without automatic logging.

🧠 Conceptual

intermediate

Which Unity method is used to add a scene to the current scenes without unloading others?

In Unity, you want to load a new scene but keep the current scene active and loaded. Which method should you use?

A SceneManager.LoadScene("NewScene", LoadSceneMode.Additive)

B SceneManager.LoadScene("NewScene")

C SceneManager.UnloadSceneAsync("CurrentScene")

D SceneManager.LoadSceneAsync("NewScene", LoadSceneMode.Single)

💡 Hint

Think about how to keep multiple scenes loaded at once.

Using LoadScene with LoadSceneMode.Additive loads the new scene without unloading the current one, allowing multiple scenes to be active simultaneously.

🔧 Debug

advanced

Why does this Unity code fail to unload a scene?

Examine the following code snippet:

using UnityEngine;
using UnityEngine.SceneManagement;

public class SceneUnloader : MonoBehaviour {
    void Start() {
        SceneManager.UnloadSceneAsync("Level1");
        Debug.Log("Unload requested");
    }
}

After running, the scene "Level1" remains loaded. What is the most likely reason?

Unity

using UnityEngine;
using UnityEngine.SceneManagement;

public class SceneUnloader : MonoBehaviour {
    void Start() {
        SceneManager.UnloadSceneAsync("Level1");
        Debug.Log("Unload requested");
    }
}

A UnloadSceneAsync requires a scene index, not a name

B UnloadSceneAsync only works in the editor, not in builds

C UnloadSceneAsync is synchronous and blocks until unload completes

D The scene "Level1" is the active scene and cannot be unloaded until another scene is active

💡 Hint

Think about Unity's rules for unloading active scenes.

Unity does not allow unloading the active scene. You must first set another scene as active before unloading the current active scene.

📝 Syntax

advanced

Which code snippet correctly loads a scene and executes code after loading completes?

You want to load a scene asynchronously and then print "Scene loaded" only after the scene finishes loading. Which code snippet is correct?

A

SceneManager.LoadScene("Level3");
Debug.Log("Scene loaded");

B

var asyncOp = SceneManager.LoadSceneAsync("Level3");
asyncOp.completed += (op) => Debug.Log("Scene loaded");

C

SceneManager.LoadSceneAsync("Level3");
Debug.Log("Scene loaded");

D

var asyncOp = SceneManager.LoadSceneAsync("Level3");
asyncOp.isDone = true;
Debug.Log("Scene loaded");

💡 Hint

Look for how to detect completion of asynchronous loading.

Option B attaches a callback to the async operation's completed event, ensuring the log runs after loading finishes. Other options either log immediately or misuse properties.

🚀 Application

expert

How many scenes are loaded after this code runs?

Given the following Unity C# code executed in a project with three scenes: "MainMenu", "Level1", and "Level2". Initially, only "MainMenu" is loaded and active.

using UnityEngine;
using UnityEngine.SceneManagement;

public class SceneTest : MonoBehaviour {
    void Start() {
        SceneManager.LoadScene("Level1", LoadSceneMode.Additive);
        SceneManager.LoadSceneAsync("Level2", LoadSceneMode.Additive);
        SceneManager.UnloadSceneAsync("MainMenu");
    }
}

After all operations complete, how many scenes remain loaded?

Unity

using UnityEngine;
using UnityEngine.SceneManagement;

public class SceneTest : MonoBehaviour {
    void Start() {
        SceneManager.LoadScene("Level1", LoadSceneMode.Additive);
        SceneManager.LoadSceneAsync("Level2", LoadSceneMode.Additive);
        SceneManager.UnloadSceneAsync("MainMenu");
    }
}

A 3 scenes: MainMenu, Level1, and Level2

B 2 scenes: Level1 and Level2

C 1 scene: Level2 only

D 2 scenes: MainMenu and Level1

💡 Hint

Consider the effect of additive loading and unloading asynchronously.

Initially MainMenu is loaded and active. Level1 loads additively synchronously, adding it. Level2 loads additively asynchronously. UnloadSceneAsync is called on MainMenu, but since it remains the active scene, it cannot be unloaded. After all operations complete, all three scenes remain loaded.

Practice

1. What is the main purpose of scenes in Unity?

easy

A. To manage player input controls

B. To write scripts for game logic

C. To create 3D models for characters

D. To organize different parts of a game like levels or menus

Solution

1. Step 1: Understand what scenes represent in Unity

   Scenes are containers that hold game objects and organize the game into parts like levels or menus.

2. Step 2: Identify the correct purpose

   Among the options, only organizing game parts matches the role of scenes.

3. Final Answer:

   To organize different parts of a game like levels or menus -> Option D

4. Quick Check:

   Scenes organize game parts = A [OK]

Hint: Scenes divide your game into levels or menus [OK]

Common Mistakes:

• Confusing scenes with scripts
• Thinking scenes create 3D models
• Mixing scenes with input management

2. Which of the following is the correct way to load a scene named "Level1" using SceneManager?

easy

A. SceneManager.LoadSceneByName("Level1");

B. SceneManager.Load("Level1");

C. SceneManager.LoadScene("Level1");

D. SceneManager.LoadSceneAsync("Level1", true);

Solution

1. Step 1: Recall the correct method to load a scene synchronously

   The official method is LoadScene with the scene name as a string.

2. Step 2: Check each option

   SceneManager.LoadScene("Level1"); uses SceneManager.LoadScene("Level1"), which is correct syntax. Others are either incorrect method names or wrong parameters.

3. Final Answer:

   SceneManager.LoadScene("Level1"); -> Option C

4. Quick Check:

   LoadScene("Level1") is correct method [OK]

Hint: Use LoadScene with scene name string [OK]

Common Mistakes:

• Using incorrect method names like Load or LoadSceneByName
• Adding extra parameters incorrectly
• Confusing async and sync loading methods

3. What will happen if you run this code snippet in Unity?

using UnityEngine.SceneManagement;

void Start() {
    SceneManager.LoadScene("Menu");
    Debug.Log("Scene Loaded");
}

medium

A. The scene "Menu" loads and then "Scene Loaded" is printed

B. Nothing happens because scenes must be loaded asynchronously

C. The code causes a compile error

D. "Scene Loaded" is printed before the scene loads

Solution

1. Step 1: Understand synchronous scene loading behavior

   LoadScene loads the new scene immediately, replacing the current one, so code after it runs only if the scene is additive or async.

2. Step 2: Analyze the code flow

   Since LoadScene is synchronous and replaces the scene immediately, the scene "Menu" loads and then "Scene Loaded" is printed.

3. Final Answer:

   The scene "Menu" loads and then "Scene Loaded" is printed -> Option A

4. Quick Check:

   LoadScene is synchronous, so log runs after scene load = A [OK]

Hint: LoadScene is synchronous; code after runs after scene loads [OK]

Common Mistakes:

• Assuming LoadScene is asynchronous
• Expecting Debug.Log after scene load
• Thinking code causes errors

4. You wrote this code to load a scene but it throws an error:

SceneManager.LoadScene(Level2);

What is the most likely cause?

medium

A. The scene name should be in quotes as a string

B. SceneManager cannot load scenes

C. You must use LoadSceneAsync instead

D. Level2 is not a valid scene name

Solution

1. Step 1: Check the syntax of LoadScene argument

   LoadScene expects a string for the scene name, so it must be in quotes.

2. Step 2: Identify the error cause

   Without quotes, Level2 is treated as a variable, causing a compile error if undefined.

3. Final Answer:

   The scene name should be in quotes as a string -> Option A

4. Quick Check:

   Scene name must be string in quotes = B [OK]

Hint: Always put scene names in quotes as strings [OK]

Common Mistakes:

• Forgetting quotes around scene names
• Assuming LoadSceneAsync is required
• Thinking SceneManager can't load scenes

5. You want to load a new scene "Level3" without unloading the current scene. Which method and parameter should you use?

hard

A. SceneManager.UnloadSceneAsync("Level3");

B. SceneManager.LoadScene("Level3", LoadSceneMode.Additive);

C. SceneManager.LoadScene("Level3", LoadSceneMode.Single);

D. SceneManager.LoadSceneAsync("Level3", true);

Solution

1. Step 1: Understand scene loading modes

   LoadSceneMode.Additive loads a scene without unloading the current one, allowing multiple scenes active.

2. Step 2: Match method and parameter

   SceneManager.LoadScene("Level3", LoadSceneMode.Additive); uses LoadScene with Additive mode, which fits the requirement. LoadScene with LoadSceneMode.Single unloads the current scene. UnloadSceneAsync unloads a scene. LoadSceneAsync expects a LoadSceneMode parameter, not a boolean.

3. Final Answer:

   SceneManager.LoadScene("Level3", LoadSceneMode.Additive); -> Option B

4. Quick Check:

   Additive mode loads scene without unloading = C [OK]

Hint: Use LoadScene with Additive mode to keep current scene [OK]

Common Mistakes:

• Using Single mode which unloads current scene
• Trying to unload instead of load
• Passing incorrect parameters to LoadSceneAsync