ULevelInstanceComponent | Unreal Engine 5.4 Documentation

Unreal Engine C++ API Reference > Runtime > Engine > LevelInstance

Inheritance Hierarchy

References


Module	Engine
Header	/Engine/Source/Runtime/Engine/Public/LevelInstance/LevelInstanceComponent.h
Include	#include "LevelInstance/LevelInstanceComponent.h"

Syntax

UCLASS (MinimalAPI)  
class ULevelInstanceComponent : public USceneComponent

Remarks

ULevelInstanceComponent subclasses USceneComponent for Editing purposes so that we can have a proxy to the LevelInstanceActor's RootComponent transform without attaching to it.

It is responsible for updating the transform of the ALevelInstanceEditorInstanceActor which is created when loading a LevelInstance Instance Level

We use this method to avoid attaching the Instance Level Actors to the ILevelInstanceInterface. (Cross level attachment and undo/redo pain)

The LevelInstance Level Actors are attached to this ALevelInstanceEditorInstanceActor keeping the attachment local to the Instance Level and shielded from the transaction buffer.

Avoiding those Level Actors from being part of the Transaction system allows us to unload that level without clearing the transaction buffer. It also allows BP Reinstancing without having to update attachements.

Constructors

	Type	Name	Description
		ULevelInstanceComponent ( const FObjectInitializer& ObjectInitializer )

Functions

	Type	Name	Description
	void	ClearCachedFilter ()
	const FWorldPartitionActorFilter &	GetFilter ()
	const TMap< FActorContainerID, TSet< FGuid > > &	GetFilteredActorsPerContainer ()
	void	OnCommit ()
	void	OnEdit ()
	void	SetFilter ( const FWorldPartitionActorFilter& InFilter, bool bNotify )
	void	UpdateEditFilter ()
	void	UpdateEditorInstanceActor ()

Overridden from USceneComponent

	Type	Name	Description
	void	OnUpdateTransform ( EUpdateTransformFlags UpdateTransformFlags, ETeleportType Teleport )	Native callback when this component is moved

Overridden from UActorComponent

	Type	Name	Description
	void	OnRegister ()	Those are the methods that need overriding to be able to properly update the AttachComponent.

Overridden from UObject

Type	Name	Description
void	PostEditChangeProperty ( FPropertyChangedEvent& PropertyChangedEvent )	Called when a property on this object has been modified externally
void	PostEditUndo ()	Called after applying a transaction to the object.
void	PreEditChange ( FProperty* PropertyAboutToChange )	This is called when a property is about to be modified externally
void	PreEditUndo ()	Called before applying a transaction to the object.
void	Serialize ( FArchive& Ar )	Handles reading, writing, and reference collecting using FArchive.

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