World Partition
Unreal Engine 5 large-world streaming
Also known as: UE5 World Partition · World Composition replacement · Level streaming grid · One File Per Actor
Definition
World Partition is Unreal Engine 5's system for building large worlds in a single level. It divides the map into a grid of cells and streams them in and out by distance from the player, so you do not have to split the map into sublevels by hand. It also saves each actor as its own file, which lets several people work on the same area at once, and it replaces the older World Composition workflow.
In production
Artists meet it in the World Partition window, in data layers and in HLODs. Avoid giant single actors that cannot be streamed, since a huge mesh or a big group of actors that crosses many cells loads together. Use data layers for things like day and night variants, and build HLODs so distant cells show a cheap proxy instead of every prop.
Tools that use World Partition
See also
HLOD
Merged proxy for distant groups of meshes
LOD
Level of Detail
Nanite
UE5 virtualized geometry
Modular Kit
Reusable building blocks for environments
Texture Streaming
Load only the mip you need
Static Mesh
Non-deforming geometry asset in Unreal Engine
Level Streaming
Load and unload parts of the world as you move
Terrain Heightmap
Grayscale image that defines terrain elevation