World Partition
- Previously manual sublevels + level streaming; file-sharing issues, hard to view whole world.
- Automatic data management and distance-based level streaming; single persistent level separated into grid cells; streaming sources load/unload cells.
- Works with One File Per Actor, Data Layers, Level Instancing, HLOD.
- Enable via Games templates (Blank/First Person/Third Person/Top Down/Vehicle Advanced have Enable Streaming disabled by default), Open World map (2 km x 2 km landscape; WP, OFPA, Data Layers, HLOD), or Convert Level / WorldPartitionConvertCommandlet.
- Actors: Runtime Grid; Is Spatially Loaded (loaded when in range of a streaming source unless in disabled Data Layer; if off, loaded unless disabled Data Layer). OFPA: no need to check out level file. Actors that reference other Actors are bundled and loaded together.
- Streaming sources: Player Controllers (Enable Streaming Source, default on); World Partition Streaming Source component (Target Grid, Target HLOD Layer, Shapes, Priority, Target State Loaded/Activated; Is Streaming Completed) — e.g. pre-load teleport destination.
- Runtime grid (World Settings): Grid Name, Cell Size (example 256 m), Loading Range (example 768 m), Block on Slow Streaming, Priority. Default 2D Runtime Hash; more than one grid can negatively impact performance. City Sample Big City recommended.
- Editor: world initially unloaded; only non-spatially-loaded actors load; load regions via World Partition window or Location Volumes. Minimap needs Virtual Textures.
- HLODs built via Build HLODs or commandlet. Cook via cook commandlet.
- Blueprint Classes preferred over Level Blueprint: actors referenced in Level Blueprint are marked Always Loaded.
- Debug: wp.Runtime.ToggleDrawRuntimeHash2D/3D, OverrideRuntimeSpatialHashLoadingRange, MaxLoadingLevelStreamingCells, wp.Runtime.HLOD 0. Builder commandlets for HLOD, nav data, resave.