🗺️ Understanding Levels

What is a Level?

Imagine you're building a museum. Each room contains different exhibits· ancient artifacts in one room, modern art in another, dinosaur fossils in a third. The building itself is your project, but each room is a distinct space with its own contents, lighting, and purpose. In Unreal Engine, a Level serves a similar role: it's a self-contained space that holds all the objects, lighting, and environmental elements for a particular scene or area.

When you create a new Unreal project, you always start with at least one level. This is your blank canvas where you'll place 3D objects, set up lighting, add interactive elements, and build your experience. Everything visible in your game at any given moment exists within a level.

What's Inside a Level?

A level contains several types of content, all working together to create your interactive environment:

• Actors: Any object placed in the world· 3D models, lights, cameras, sound sources, triggers, and more
• Environment Settings: Lighting configuration, sky atmosphere, fog, and post-process effects that define the scene's mood
• Gameplay Elements: Player start locations, spawn points, navigation meshes, and collision volumes
• World Settings: Level-specific configuration like physics settings, gravity, and game mode rules

File Structure

Levels are saved as files with the .umap extension (short for "Unreal Map"). You'll find them in your project's Content folder, typically organized in a Maps or Levels subfolder. When you open a project, Unreal loads one of these .umap files into the editor, displaying all the actors and settings it contains.

Why Multiple Levels Matter

While you could build an entire game in a single level, there are compelling reasons to split your project into multiple levels:

1. Performance: Loading and rendering everything at once is inefficient. Splitting your world into separate areas means the engine only loads what's currently needed, improving performance and reducing memory usage. (As you'll see next, World Partition can do this splitting for you inside a single level.)
2. Organization: Smaller, focused levels are easier to manage, especially when working with a team. One person can work on the forest area while another builds the cave system.
3. Testing: You can quickly jump to specific areas to test gameplay without navigating through the entire world each time.
4. Variety: Different levels can have completely different aesthetics, lighting, and gameplay styles· think of transitioning from a sunny village to a dark dungeon.

Figure: A typical game project organized into multiple distinct levels

World Partition & Level Streaming

How does Unreal load a massive, seamless world without running out of memory? The answer has changed. In Unreal Engine 4 and the earliest UE5 releases, developers built large maps by hand: you sliced the world into sublevels and used the Level Streaming system to load and unload each one as the player moved. This worked, but it was manual, error-prone, and awkward for teams. Unreal Engine 5 introduced World Partition to automate the whole process, and in UE 5.8 it is the standard way to build large worlds.

In Epic's own words, "Building large maps used to require developers to manually divide maps into sublevels, then use the Level streaming system to load and unload them as the player traversed the landscape." World Partition removes that manual step entirely: you build in one continuous level, and the engine handles the streaming grid for you.

How World Partition Works

When World Partition is enabled, a few systems work together behind the scenes:

• Grid-based streaming: The world is divided into square cells. Only cells within a loading range of the player (or camera) are kept in memory, so a 10 km world costs about the same to run as a small one.
• One File Per Actor (OFPA): Each actor is saved as its own small file instead of everything living in one giant .umap. This is what makes World Partition great for teams· two people can edit different parts of the same world at once without locking each other out of the file.
• HLOD (Hierarchical Level of Detail): Distant cells that aren't loaded are still represented by lightweight, auto-generated proxy meshes, so faraway mountains and skylines remain visible without their full geometry in memory.
• The World Partition editor: A minimap grid inside the editor lets you load, unload, and focus on regions of the world while you work, so you never have to open the entire map at once.

Persistent Levels and Streaming Levels

World Partition doesn't throw away the older ideas· it builds on them. It's worth knowing the two terms it automates, because they still appear throughout the editor and in many existing projects.

A persistent level is the "main" level that stays loaded for the whole session. It's the foundation. With World Partition, your single world is a persistent level, and the streaming grid loads content into it. In a small project with just one level, that level is simply persistent by default.

A streaming level (also called a "sublevel") is a level that loads or unloads dynamically at runtime. Before World Partition, you added these by hand in the Levels panel and controlled them yourself. That manual workflow still exists in UE 5.8· it's the right tool for a few specific jobs, but it is no longer how you build a big open world.

When to Use Each Approach

The mermaid diagram below shows the streaming idea in the abstract: a persistent level stays put while nearby areas load and far ones unload. With World Partition this happens automatically per grid cell· with manual Level Streaming you wire it up yourself.

Figure: Content near the player loads while distant content unloads, all around a constant persistent level

Level Organization Strategies

As your projects grow in complexity, having a clear organizational strategy becomes essential. Some of these patterns are about the flow between distinct levels; others are about how you structure a single World Partition world. Let's look at the common ones.

Strategy 1: Linear Level Progression

This is the simplest approach and works well for games with distinct, sequential stages· think of classic platformers or action games where you progress from Level 1 to Level 2 to Level 3.

Structure:

• MainMenu.umap - The starting point
• Level_01_Tutorial.umap - First playable level
• Level_02_Forest.umap - Second level
• Level_03_Cave.umap - Third level
• Level_04_Boss.umap - Climactic encounter

Pros: Simple to manage, easy to test individual levels, clear progression flow

Cons: Each transition requires loading a new level, less suitable for open-world designs

Figure: Linear level progression with distinct stages

Strategy 2: Hub-and-Spoke

This pattern uses a central "hub" area that connects to multiple separate zones. Think of games like Dark Souls (Firelink Shrine) or Splatoon (Inkopolis Square), where you return to a central location between missions or areas.

Structure:

• Hub_CentralTown.umap - The main hub level
• Mission_Forest.umap - Accessed from the hub
• Mission_Desert.umap - Accessed from the hub
• Mission_Ruins.umap - Accessed from the hub
• Mission_FinalBoss.umap - Unlocked after completing other missions

Pros: Provides a sense of centralization, easy to add new content, players have a "home base"

Cons: Requires transitions between hub and missions, can feel repetitive if overused

Figure: Hub-and-spoke pattern with a central location connecting to multiple zones

Strategy 3: Open World with World Partition

Modern open-world games use this approach to create vast, seamless environments. In older Unreal versions you hand-authored a region sublevel for every zone (Region_City_North.umap, Region_Forest_East.umap, and so on) and wired up their streaming yourself. In UE 5.8 you don't do that anymore: you build the whole world in one World Partition level, and the streaming grid loads regions automatically based on player proximity.

Structure (a single level):

• World_Open.umap - One persistent World Partition level containing the entire landscape
• Sky, lighting, and global systems live directly in that level
• Cities, forests, and mountains are just regions of the same map, streamed by the grid
• Each actor is its own file (One File Per Actor), so a whole team can build the world in parallel

Pros: Seamless exploration, no loading screens, feels like one continuous world, no manual streaming setup

Cons: Requires thoughtful optimization (HLOD, cell sizes), and testing a specific spot means loading that region

Strategy 4: Data Layers (Layered Content)

Sometimes you want to organize content not by location but by purpose: all the lighting together, all the gameplay actors together, a separate day and night dressing of the same space. In UE 5.8 the modern tool for this is Data Layers, a World Partition feature that tags actors into layers you can show, hide, or swap· both in the editor and at runtime· all within a single level.

• Editor Data Layers: Toggle sets of actors on and off while you work (for example, hide all foliage to edit the terrain underneath)
• Runtime Data Layers: Switch content in and out during gameplay (a "day" dressing vs. a "night" dressing, or a quest state that adds rubble to a town)

Pros: Excellent for team collaboration and variations, no separate sublevel files to juggle, integrates with World Partition streaming

Cons: Requires discipline to assign actors to the right layers, and is a World Partition concept (so it lives inside a partitioned world)

Choosing Your Approach

Which strategy should you use? Consider these factors:

• Project scope: Small games can use a single level with linear or hub flow; large games use one World Partition world
• Team size: Solo developers might prefer simplicity; teams benefit from World Partition's One File Per Actor and Data Layers
• Performance targets: Mobile or VR projects need careful streaming and HLOD tuning to hold frame rate
• Genre conventions: Platformers often use discrete linear levels; open-world RPGs use World Partition

Don't be afraid to start simple and evolve your structure as needed. Many projects begin with a single Basic level and adopt World Partition or multiple levels only when performance or scope demands it.

The World Settings Panel

Every level in Unreal Engine has a World Settings panel that controls level-specific configuration. Think of it as the "properties" for the entire level· settings that affect everything within that particular world.

Accessing World Settings

To open the World Settings panel, use either route:

1. From the menu bar, choose Window → World Settings, or
2. From the main toolbar, click the Settings (gear) dropdown and select World Settings

The panel opens as a tab on the right side of the editor, alongside (or where) the Details panel appears. You'll see it has multiple collapsible categories with numerous options.

Figure: The World Settings panel in UE 5.8 · note the World Partition Setup category right at the top, with Enable Streaming ticked, followed by Game Mode, Physics, World (Kill Z), and VR settings.

Important World Settings

Let's explore the most commonly used settings you'll encounter, working roughly top to bottom through the panel above:

World Partition Setup

At the very top of World Settings sits the World Partition Setup category· this is where UE 5.8 exposes the automatic streaming system we covered earlier.

• Enable Streaming: Turns the World Partition grid on or off for this level. When it's on, the world streams cell by cell as the player moves.
• Runtime Hash Class: Defines how the world is partitioned into a runtime grid (the default hash set works for most worlds).
• Default HLOD Layer: Sets which Hierarchical LOD layer generates the proxy meshes shown for distant, unloaded cells.

Game Mode

The GameMode Override setting determines which set of rules and logic applies to this level. Different levels can use different game modes· for example, your main menu might use one game mode, while gameplay levels use another.

• What it does: Defines player classes, HUD, victory conditions, and gameplay rules
• Common use: Setting a custom game mode for this specific level
• Example: Using a "MainMenuGameMode" for your start screen, then a "FPSGameMode" for shooting levels

Physics Settings

You can override global physics settings for this specific level:

• Override World Gravity: Enables a per-level gravity value instead of the project default
• Global Gravity Z: The gravity strength for the level (the project default is -980 cm/s², which matches Earth's gravity)
• Example use: Creating a moon level with lower gravity (-162 cm/s²) or a zero-gravity space station

Kill Z (Death Plane)

Under the World category, the Kill Z setting defines a height below which actors are automatically destroyed. This prevents players who fall off the world from falling forever.

• What it does: Any actor that falls below this Z-coordinate is destroyed
• Default value: Set very low (the level captured above reads -1048575, far below the playable space)
• Example use: In a platformer, ensuring players respawn after falling into a pit

World to Meters & Other Categories

Further down you'll find categories like VR (whose World to Meters value maps Unreal units to real-world scale for XR), Lightmass (baked-lighting quality), and audio-related settings that define how sound behaves in the level. As a beginner you won't need to touch most of these· the defaults work well for typical projects· but knowing they exist helps you understand how Unreal gives you fine-grained control over every level.

Creating and Saving New Levels

Now that you understand what levels are and how they're organized, let's walk through the practical steps of creating and managing levels in Unreal Engine 5.8.

Creating a New Level

Go to File → New Level in the menu bar. The New Level dialog opens with the UE 5.8 template choices:

• Open World: A large, streamable world with sample content and World Partition already enabled· the starting point for open-world projects
• Empty Open World: A World Partition world with no content, ready for you to build a large map from scratch
• Basic: A simple level with a floor plane, lighting, sky atmosphere, and exponential height fog· ideal for smaller scenes and for learning
• Empty Level: A completely blank level with no actors at all

Pick a template and click Create.

Creating a Level from the Content Browser

1. Open the Content Browser
2. Navigate to the folder where you want the level (typically Content/Maps/)
3. Click + Add (or right-click in an empty space) and choose Level
4. The new level file appears· give it a meaningful name

This keeps the level file directly in your chosen folder, keeping your project organized from the start.

Saving Your Level

After creating or modifying a level, you need to save it. Unreal uses two types of saves:

Save Current Level

• Shortcut: Ctrl + S
• Menu: File → Save Current Level
• What it does: Saves only the currently open level

If this is the first time saving a new level, a dialog appears asking where to save it and what to name it. Choose a descriptive name like Tutorial_Level or Forest_Area_01.

Save All

• Shortcut: Ctrl + Shift + S
• Menu: File → Save All
• What it does: Saves every modified level and asset currently loaded (useful with streaming levels or World Partition, where many actor files may be dirty)

Opening Existing Levels

To open a level you've previously created or one that came with your project:

1. Method 1 (File Menu): Go to File → Open Level, then browse to the .umap file
2. Method 2 (Content Browser): Navigate to your Maps folder, double-click the level's thumbnail
3. Method 3 (Recent Levels): Go to File → Open Recent to see a list of recently opened levels

When you open a different level, Unreal closes the current one. Any unsaved changes prompt a save dialog first.

Level Naming Best Practices

Professional projects use consistent naming conventions. Here are some common patterns:

Avoid generic names like Level1, NewMap, or Untitled. Future-you (and your teammates) will thank you for using clear, descriptive names.

Summary

In this lesson, you've learned the foundational concepts of how Unreal Engine 5.8 organizes 3D worlds using levels. Let's recap the key points:

Key Takeaways

• 📦 Levels are containers that hold all the objects, lighting, and gameplay elements for a scene or area, saved as .umap files
• 🌍 World Partition is the UE 5.8 default for large worlds· it stores the world in one persistent level and streams a grid of cells automatically, with One File Per Actor and HLOD
• 🏗️ Persistent and streaming levels are the concepts World Partition automates; manual Level Streaming still exists for specific cases, while World Composition is now legacy
• 🗂️ Organization strategies range from linear and hub-and-spoke flows between levels to Data Layers inside a single World Partition world
• ⚙️ World Settings control level-specific configuration· World Partition Setup, game mode, physics, and Kill Z
• 💾 Creating and saving levels uses the Open World, Empty Open World, Basic, and Empty Level templates· pick Basic for learning, Open World for large worlds

What's Next?

Now that you understand how levels work, the next step is populating them with content. In Lesson 2.2: Actors and Components, you'll learn about the building blocks that go inside levels· the objects, lights, sounds, and gameplay elements that bring your worlds to life.