UE5 Levels & Maps

Best practices for level organization and World Partition in Unreal Engine 5.

Folder Organization

All maps in a dedicated folder:

code

Content/
└── ProjectName/
    └── Maps/
        ├── MainMenu/
        │   └── L_MainMenu.umap
        ├── Gameplay/
        │   ├── L_Level01.umap
        │   └── L_Level02.umap
        └── Test/
            └── L_TestMap.umap

World Partition (UE5)

Strongly recommended - replaces legacy level streaming.

Benefits

Feature	Description
Grid-based streaming	Automatic cell loading/unloading
One-file-per-actor	Better team collaboration
Data Layers	Runtime actor organization
No manual streaming volumes	Automatic based on distance

Setup

•Create new level with World Partition enabled
•Configure grid cell size (default: 12800 units)
•Set up streaming sources

Data Layers

Organize actors and toggle visibility at runtime:

Layer Type	Use Case
Runtime Data Layers	Toggle at runtime (day/night variants)
Editor Data Layers	Editor organization only

cpp

// Toggle data layer at runtime
UDataLayerSubsystem* DataLayerSubsystem = GetWorld()->GetSubsystem<UDataLayerSubsystem>();
DataLayerSubsystem->SetDataLayerRuntimeState(DataLayer, EDataLayerRuntimeState::Activated);

Streaming Sources

Control what areas load based on:

Source	Description
PlayerController	Default, loads around players
Custom Sources	Cameras, vehicles, AI

cpp

// Register custom streaming source
GetWorld()->GetWorldPartition()->RegisterStreamingSourceProvider(MyStreamingSource);

One-File-Per-Actor (OFPA)

Enable for team collaboration:

Benefit	Description
Reduced conflicts	Each actor in separate file
Parallel work	Multiple team members, same level
Better diffs	Smaller, focused changes

Quality Checklist

Check	Description
Zero map errors	Run Map Check, fix all issues
Zero warnings	Address all warnings
Lighting built	Build lighting before distribution
No Z-fighting	Fix overlapping geometry
Streaming tested	Verify smooth loading

Best Practices

Practice	Reason
Use World Partition	Modern streaming, collaboration
Enable OFPA	Team workflow
Set up Data Layers	Runtime organization
Configure grid size appropriately	Balance streaming granularity
Test streaming on target hardware	Verify performance

Legacy Level Streaming

If not using World Partition:

code

Persistent Level
├── Sublevel_Gameplay
├── Sublevel_Lighting
├── Sublevel_Audio
└── Sublevel_Cinematics

Use Level Streaming Volumes or Blueprint to control loading.

Performance Tips

Tip	Benefit
Appropriate grid cell size	Balance load frequency vs. memory
HLOD for distant objects	Reduced draw calls
Proper actor bounds	Accurate culling
Streaming source priorities	Load important areas first

Common Issues

Issue	Solution
Actors not streaming	Check grid placement, bounds
Slow loading	Reduce cell size, optimize assets
Pop-in	Adjust loading distance, use HLOD
Collaboration conflicts	Enable OFPA

Documentation: https://dev.epicgames.com/documentation/en-us/unreal-engine/world-partition-in-unreal-engine