Full Class Catalog¶

A reference flattening of UE's primary blueprint-relevant classes. Use this when you can't remember what a class is for.

Game framework¶

Class	Role
`UGameInstance`	Persists across levels; per-process singleton
`AGameModeBase`	Server-side game rules; not replicated
`AGameStateBase`	Replicated game state visible to all clients
`APlayerState`	Per-player replicated state (score, name)
`APlayerController`	Per-player local input + camera authority
`AAIController`	NPC controller
`AHUD`	Per-player UI root
`APawn` / `ACharacter`	Possess-able actors
`ULevelScriptActor`	Per-level Blueprint logic

Class	Role
`AActor`	Base placeable
`AStaticMeshActor`	Wrapped `UStaticMeshComponent`
`ASkeletalMeshActor`	Wrapped `USkeletalMeshComponent`
`ABrush`	CSG / volume base
`AVolume`	Bounded region
`ATriggerVolume`, `APostProcessVolume`, `AAudioVolume`, …	Specific volumes (see Volumes)
`ACameraActor` / `ACineCameraActor`	Placed cameras
`ADecalActor`	Decals
`AEmitter` (legacy) / `ANiagaraActor`	FX

Class	Role
`UStaticMeshComponent`	Static mesh rendering + collision
`USkeletalMeshComponent`	Skinned mesh
`UInstancedStaticMeshComponent`	Many identical meshes, one draw call
`UHierarchicalInstancedStaticMeshComponent`	ISM + LOD per instance
`UCharacterMovementComponent`	Pawn locomotion
`UAbilitySystemComponent`	GAS hub
`USceneCaptureComponent2D`	Camera into RT
`UWidgetComponent`	UMG in 3D
`UNiagaraComponent`	FX instance
`UAudioComponent`	Sound instance
`UCameraComponent`	POV
`USpringArmComponent`	Third-person follow boom

Class	Role
`UWidget`	Base
`UUserWidget`	Composite (your Widget Blueprints)
`UCommonActivatableWidget`	Common UI stack member
`UCommonButtonBase`	Common UI button
`UWidgetComponent`	3D-placed widget

Class	Role
`USkeletalMeshComponent`	Renders + ticks an AnimInstance
`UAnimInstance`	Anim Blueprint runtime
`UAnimSequence`	A baked clip
`UAnimMontage`	Sectioned playback for combos / cinematics
`UAnimBlueprint`	Authoring asset for `UAnimInstance`
`UControlRig`	Procedural rigging
`UIKRig`	Skeleton retargeting / IK
`UPoseAsset`	Library of named poses
`UAnimDataModel`	Internal anim authoring model

Class	Role
`UDataAsset` / `UPrimaryDataAsset`	Data containers
`UDataTable`	Tabular data
`UCurveBase` / `UCurveFloat` / `UCurveVector`	Time-based curves
`UCompositeDataTable`	Layered data tables
`UGameplayTagsManager`	Tag registry

Class	Role
`UBehaviorTree`	The BT asset
`UBlackboard`	Keyed data store for BTs
`UBTService` / `UBTTask` / `UBTDecorator`	BT node types
`UEnvQueryTest` / `UEnvQuery`	EQS spatial queries
`UAIPerceptionComponent`	Sight / hearing
`AAIController`	The NPC's controller
`UNavigationSystem`	Project-wide nav

Class	Role
`UTexture2D`	Standard 2D texture
`UTextureRenderTarget2D`	Writable RT
`UMaterial`	Master material
`UMaterialInstance{Constant,Dynamic}`	Static / runtime instance
`UStaticMesh` / `USkeletalMesh`	Source meshes
`UWorld`	The level container
`UPostProcessSettings`	Post-process struct (used in volumes / cameras)

Subsystems are the modern replacement for singletons — UMySubsystem* S = GetGameInstance()->GetSubsystem<UMySubsystem>();.

When you're sketching a system, glance here to find the right starting class. From there, the per-page deep dives explain how to use them.