Prefabs and reusable objects in Unity - Step-by-Step Execution

Concept Flow - Prefabs and reusable objects

Create GameObject

↓

Configure GameObject

↓

Create Prefab from GameObject

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Use Prefab in Scene

↓

Modify Prefab

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Prefab Updates All Instances

You create a game object, turn it into a prefab, then reuse it many times. Changing the prefab updates all copies.

Execution Sample

Unity

GameObject enemy = new GameObject("Enemy");
// Add components and set properties
PrefabUtility.SaveAsPrefabAsset(enemy, "Assets/Resources/Prefabs/Enemy.prefab");

// Later in scene
GameObject enemyInstance = Instantiate(Resources.Load<GameObject>("Prefabs/Enemy"));

Create an enemy object, save it as a prefab, then create instances from that prefab in the scene.

Execution Table

Step	Action	Object State	Prefab State	Result
1	Create GameObject 'Enemy'	Enemy created, no prefab	No prefab yet	GameObject exists in scene
2	Configure Enemy (add components)	Enemy has components	No prefab yet	GameObject ready for prefab
3	Save as prefab 'Enemy.prefab'	Enemy linked to prefab	Prefab saved with Enemy data	Prefab asset created
4	Instantiate prefab in scene	New Enemy instance created	Prefab unchanged	Instance appears in scene
5	Modify prefab asset	Prefab updated	Prefab asset changed	All instances update automatically
6	Modify instance only	Instance changed	Prefab unchanged	Instance overrides prefab settings
7	Exit	-	-	No more actions

💡 No more actions to perform; prefab and instances are set up.

Variable Tracker

Variable	Start	After Step 1	After Step 3	After Step 4	After Step 5	Final
enemy (GameObject)	null	Created (no prefab)	Linked to prefab	Instance created	Prefab updated	Prefab and instances synced
prefab (Asset)	null	null	Created with enemy data	Unchanged	Updated	Updated prefab asset

Key Moments - 3 Insights

Why does changing the prefab update all instances automatically?

Because all instances are linked to the prefab asset, so when the prefab changes (see step 5 in execution_table), Unity updates all instances to match.

What happens if you change only one instance and not the prefab?

The instance overrides the prefab settings locally (step 6), so that instance looks different but the prefab and other instances stay the same.

Why do we create a prefab instead of just copying GameObjects?

Prefabs let you reuse objects easily and update all copies at once, unlike copies which are independent and need manual updates.

Visual Quiz - 3 Questions

Look at the execution_table, at which step is the prefab asset first created?

A Step 1

B Step 3

C Step 4

D Step 5

💡 Hint

Check the 'Prefab State' column in execution_table rows.

According to variable_tracker, what is the state of 'enemy' after step 4?

A Created but no prefab

B Linked to prefab

C Instance created

D Prefab updated

💡 Hint

Look at the 'enemy (GameObject)' row under 'After Step 4' in variable_tracker.

If you modify only one instance (step 6), what happens to the prefab asset?

A Prefab asset remains unchanged

B Prefab asset is deleted

C Prefab asset updates

D Prefab asset duplicates

💡 Hint

See 'Prefab State' column in execution_table at step 6.

Concept Snapshot

Prefabs are reusable game object templates.
Create a GameObject, configure it, then save as prefab.
Instantiate prefab copies in scenes.
Changing prefab updates all instances.
Instance changes override prefab locally.

Full Transcript

Prefabs in Unity let you create a game object once and reuse it many times. First, you create and set up a GameObject, then save it as a prefab asset. This prefab acts like a template. When you add prefab instances to your scene, they link back to the prefab. If you change the prefab asset, all instances update automatically. But if you change only one instance, it overrides the prefab locally without affecting others. This system helps keep your game organized and easy to update.