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Blueprints

Unreal's visual scripting + class system. Every "Blueprint" is a subclass of some native C++ UObject — the BP system simply lets you author classes and graphs visually.

Top-level class hierarchy

UObject
├── UActorComponent
│   └── USceneComponent
│       ├── UStaticMeshComponent
│       ├── USkeletalMeshComponent
│       ├── UWidgetComponent
│       ├── USceneCaptureComponent2D
│       └── ...
├── AActor
│   ├── APawn
│   │   └── ACharacter
│   ├── AController
│   │   ├── APlayerController
│   │   └── AAIController
│   ├── AGameModeBase
│   ├── AGameStateBase
│   ├── APlayerState
│   ├── ALevelScriptActor
│   ├── AHUD
│   ├── AVolume
│   └── ...
├── UWidget (UMG)
│   └── UUserWidget
├── UAnimInstance
├── UDataAsset
├── UBlueprintFunctionLibrary
├── USaveGame
└── UInterface

Page index

Topic Page
AActor — base game object →
APawn / ACharacter — player/AI controlled →
UActorComponent / USceneComponent →
UMG / UUserWidget →
UAnimInstance →
UDataAsset / Primary Data Asset →
Gameplay Ability System (GAS) →
Full catalog →

Blueprint asset types

Asset Backing class Use
Blueprint Class Any UObject Author a new subclass
Widget Blueprint UUserWidget UMG screens
Animation Blueprint UAnimInstance Skeletal animation logic
Blueprint Function Library UBlueprintFunctionLibrary Static helper functions
Blueprint Macro Library (special) Reusable subgraphs
Blueprint Interface UInterface Cross-class contracts
Editor Utility Blueprint UEditorUtilityObject Editor-time scripting
Editor Utility Widget UEditorUtilityWidget In-editor UMG tools
Primary Data Asset UPrimaryDataAsset Data-driven content
Data Asset UDataAsset Simple data containers
Game Instance UGameInstance Persists across levels
Game Mode AGameModeBase Server rules
Game State AGameStateBase Replicated server state
Player Controller APlayerController Per-player input
HUD AHUD Per-player UI root

Pure vs Impure nodes

  • Pure (green): no execution pin; idempotent; safe to call multiple times
  • Impure (blue): execution pins; side effects

Blueprint vs C++

Concern Blueprint C++
Iteration speed ★ Recompile required
Performance ~10× slower per call Native speed
Refactoring Painful for large graphs IDE-supported
Designer-friendly ★ No
Multi-frame logic / latent nodes First-class Manual state machine

Rule of thumb: C++ for systems and hot paths, Blueprint for content and gameplay assembly.

See also