Level

A scene containing actors, lighting, geometry. Open a level via Open Level. Sublevels stream in/out.

Level transition: save data then open new level

Pattern: custom trigger or UI button → [save player data to SaveSlot] → OpenLevel(LevelName='Level_02', bAbsolute=true, Options=''). For loading screen: SetGlobalTimeDilation(0.001) briefly while level loads (freeze world), or use AsyncLoadLevel with progress callback. Key: OpenLevel is in GameplayStatics. 'LevelName' is the map asset name (not full path). bAbsolute=true discards current level completely. Options string can pass params like '?GameMode=BP_GM'.

Sublevel

A child level streamed in/out of a persistent level. Used for open-world streaming and modular maps.

OpenLevel — load a level by name

UGameplayStatics::OpenLevel. Use OpenLevelBySoftObjectPtr for asset references.

GetCurrentLevelName — get name of the current level

GetTimeSeconds — time elapsed since level started in seconds

Pure node. Useful for time-based calculations. Resets when level loads.

GetGameInstance — get the GameInstance (persists across levels)

Pure node. Ideal for storing data that persists across level loads.

GetTimeSeconds — get time since level started

Actor

Anything that can be placed in a Level. Has a Transform. Player characters, props, lights, and triggers all inherit from Actor.

GameMode

Defines the rules + default classes (Pawn, PlayerController, GameState) for a level. Only exists on the server.