In this lesson, you will learn how to load multiple scenes simultaneously to organize your game world into manageable, modular segments.
Why Load Additively?
Imagine building a sprawling open-world game. If you try to fit every tree, building, and lighting setup into a single scene, your project will quickly become cluttered and difficult to manage. Additive Loading allows you to keep your base environment in one scene and "add" additional scenes—like an interior house, a dungeon, or a UI overlay—on top of it without clearing the current one.
When you load a scene additively, Unity preserves your current hierarchy while appending the objects from the new scene underneath it. This means you can keep your "Main World" active while toggling the visibility or presence of smaller, modular sections.
How to Implement Additive Loading
To load a scene while keeping the current one, we use the SceneManager. In a C# script, you specify the name of the scene and set the LoadSceneMode to Additive.
using UnityEngine;
using UnityEngine.SceneManagement;
public class LevelLoader : MonoBehaviour
{
public void LoadDungeon()
{
// This keeps the current scene active and adds 'DungeonScene' to it
SceneManager.LoadScene("DungeonScene", LoadSceneMode.Additive);
}
}
Managing Your Hierarchy
When multiple scenes are loaded, you will notice the Hierarchy window displays them as separate "Roots." This is great for organization! Because each scene maintains its own hierarchy, you can effectively separate your lighting, terrain, and gameplay logic into their own files. If you decide you don't need the "Dungeon" anymore, you can use SceneManager.UnloadSceneAsync("DungeonScene") to remove it from memory, keeping your project performant and clean.
By combining additive scenes with the organizational skills you learned in previous lessons—such as using Empty GameObjects for grouping or Prefabs for structure—you can build complex, layered worlds that remain easy to edit and maintain.
Key Takeaway: Additive loading allows you to layer multiple scenes together in the hierarchy, enabling modular level design without losing your current progress or world state.