Scene hierarchy window in Unity - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Unity C# script affecting the hierarchy?

Consider the following Unity C# script attached to a GameObject in a scene. What will be printed in the Console when the scene starts?

Unity

using UnityEngine;

public class HierarchyTest : MonoBehaviour {
    void Start() {
        Debug.Log(transform.childCount);
        foreach (Transform child in transform) {
            Debug.Log(child.name);
        }
    }
}

A The number of children of the GameObject, followed by each child's name on a new line

B 0

C NullReferenceException at runtime

D The name of the GameObject only

💡 Hint

Think about what transform.childCount returns and how foreach over transform works.

transform.childCount returns how many children the GameObject has. The foreach loop iterates over each child Transform, printing their names.

🧠 Conceptual

intermediate

Which statement about the Scene Hierarchy window is true?

Select the correct statement about the Unity Scene Hierarchy window.

A It shows GameObjects from all loaded scenes combined.

B It only shows GameObjects that are active in the scene.

C It shows all GameObjects in the current scene including inactive ones.

D It allows editing of GameObject components directly.

💡 Hint

Think about whether inactive GameObjects appear in the hierarchy.

The Scene Hierarchy window shows all GameObjects in the current scene, including those that are inactive. Inactive GameObjects appear grayed out.

🔧 Debug

advanced

Why does this code not find a child GameObject in the hierarchy?

This code tries to find a child GameObject named "Enemy" but always returns null. Why? GameObject enemy = transform.Find("Enemy").gameObject;

A The code should use GameObject.Find instead of transform.Find.

B The child "Enemy" is nested deeper than one level, so transform.Find("Enemy") returns null.

C The child "Enemy" is inactive, so transform.Find cannot find it.

D The child "Enemy" does not exist in the scene at all.

💡 Hint

Remember how transform.Find works with paths and direct children.

transform.Find only finds direct children or children by path. If "Enemy" is nested deeper without a path, it returns null.

📝 Syntax

advanced

Which code snippet correctly moves a GameObject under a new parent in the hierarchy?

Select the correct code to set the parent of a GameObject named "child" to another GameObject named "parent".

A child.transform.SetParent(parent.transform);

B child.parent = parent.transform;

C child.transform.SetParent(parent);

D child.transform.parent = parent.transform;

💡 Hint

Check the correct method and parameter type for setting a parent transform.

SetParent expects a Transform parameter. parent is a GameObject, so use parent.transform.

🚀 Application

expert

How many GameObjects will be active in the scene after this code runs?

Given a GameObject "Root" with 3 children: "A" (active), "B" (inactive), and "C" (active). The code below runs: foreach (Transform child in root.transform) { child.gameObject.SetActive(false); } root.SetActive(true);

A 4

B 3

C 0

D 1

💡 Hint

Remember what SetActive does to children and the parent separately.

The code disables all children, so none are active. The root remains active, so only 1 GameObject is active.