Level Streaming
Load and unload parts of the world as you move
Also known as: Streaming levels · Sublevels · Additive scene loading · Open world streaming · Addressables streaming
Definition
Level streaming loads and unloads parts of a game world while the player moves, so only the nearby parts are in memory, and large worlds fit in limited resources. In Unreal Engine, streaming can use sublevels and, in Unreal Engine 5, World Partition, which streams by distance in a grid. In Unity, additive scene loading and Addressables stream chunks of content. Well-planned streaming removes loading screens and keeps memory use under control.
In production
Split the world by gameplay and visibility, keep the boundaries away from places the player can see across, and make sure large assets belong to a single cell. Hitches usually come from streaming too much at once or too late, so tune distances and prioritize what is close. Textures stream separately from levels, and both can cause pop-in, which you can reduce by a good LOD and fog setup.
