Instantiating objects at runtime in Unity - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Unity C# code when instantiating a GameObject?

Consider the following Unity C# script attached to an empty GameObject in the scene. What will be printed in the console when the game starts?

Unity

using UnityEngine;

public class InstantiateTest : MonoBehaviour
{
    public GameObject prefab;

    void Start()
    {
        GameObject obj = Instantiate(prefab);
        Debug.Log(obj.name);
    }
}

A "prefab"

B "prefab(Clone)"

C "obj"

D NullReferenceException

💡 Hint

When you instantiate a prefab in Unity, the new object's name usually has a suffix added.

Unity adds "(Clone)" to the name of instantiated GameObjects to distinguish them from the original prefab asset.

🧠 Conceptual

intermediate

Which method is used to instantiate objects at runtime in Unity?

In Unity C#, which method is used to create a copy of a GameObject during runtime?

A GameObject.Copy()

B CreateInstance()

C CloneObject()

D Instantiate()

💡 Hint

Think about the method that duplicates objects in Unity scripts.

The Instantiate() method is the standard way to create copies of GameObjects or prefabs at runtime in Unity.

🔧 Debug

advanced

What error does this code produce when instantiating a prefab without assigning it?

Examine the code below. What error will occur when running this script if the prefab variable is not assigned in the Inspector?

Unity

using UnityEngine;

public class SpawnObject : MonoBehaviour
{
    public GameObject prefab;

    void Start()
    {
        GameObject obj = Instantiate(prefab);
    }
}

A NullReferenceException

B MissingReferenceException

C ArgumentNullException

D No error, object instantiated as empty

💡 Hint

What happens if you try to use a variable that has not been set?

If prefab is null, calling Instantiate(prefab) causes a NullReferenceException because you cannot instantiate a null object.

📝 Syntax

advanced

Which option correctly instantiates a prefab at a specific position and rotation?

Choose the correct syntax to instantiate a prefab at position (0, 1, 0) with no rotation in Unity C#.

A Instantiate(prefab, new Vector3(0, 1, 0), 0);

B Instantiate(prefab, Vector3(0, 1, 0), Quaternion.identity);

C Instantiate(prefab, new Vector3(0, 1, 0), Quaternion.identity);

D Instantiate(prefab, (0, 1, 0), Quaternion.identity);

💡 Hint

Remember how to create a Vector3 and use Quaternion for rotation.

Instantiate requires a Vector3 position and a Quaternion rotation. Vector3 must be created with new Vector3(x, y, z).

🚀 Application

expert

How many GameObjects are created after running this code snippet?

Given the following Unity C# code, how many GameObjects will exist in the scene after Start() finishes?

Unity

using UnityEngine;

public class MultiInstantiate : MonoBehaviour
{
    public GameObject prefab;

    void Start()
    {
        for (int i = 0; i < 3; i++)
        {
            Instantiate(prefab);
        }
        Instantiate(prefab);
    }
}

A 4

B 1

C 0

D 3

💡 Hint

Count how many times Instantiate is called in total.

The loop runs 3 times, each calling Instantiate once, plus one more Instantiate call after the loop, totaling 4 GameObjects created.