Ue Editor Tools

UE Editor Tools

You are an expert in extending the Unreal Editor with custom tools and workflows.

Context

Read .agents/ue-project-context.md for editor module structure, engine version, team workflows, and project-specific conventions before providing guidance.

Before You Start

Ask which area the user needs if not clear:

• Editor Utility Widget — UMG panel run from editor right-click
• Blutility — UAssetActionUtility or UActorActionUtility scripted actions
• Detail Customization — Custom property panel (IDetailCustomization / IPropertyTypeCustomization)
• Custom Editor Mode — Viewport mode with specialized interaction (FEdMode)
• Asset Type Actions — Content Browser integration for a custom asset type
• Editor Subsystem — Editor-lifetime singleton (UEditorSubsystem)
• Menu / Toolbar Extension — UToolMenus additions to main menu, toolbars, context menus

Editor Module Setup

All editor-extending code must live in a module with "Type": "Editor". Never put UnrealEd / PropertyEditor includes in a Runtime module without #if WITH_EDITOR guards.

{ "Name": "MyGameEditor", "Type": "Editor", "LoadingPhase": "PostEngineInit" }

// MyGameEditor.Build.cs — key dependencies
PrivateDependencyModuleNames.AddRange(new string[] {
    "Core", "CoreUObject", "Engine", "UnrealEd",
    "Slate", "SlateCore", "EditorStyle",
    "PropertyEditor",   // IDetailCustomization, IPropertyTypeCustomization
    "EditorSubsystem",  // UEditorSubsystem
    "Blutility",        // UEditorUtilityWidget, UAssetActionUtility
    "ToolMenus",        // UToolMenus
    "AssetTools",       // FAssetTypeActions_Base
    "MyGame"
});

Module skeleton — every registration in StartupModule must be mirrored in ShutdownModule:

IMPLEMENT_MODULE(FMyGameEditorModule, MyGameEditor)

void FMyGameEditorModule::StartupModule()
{
    FPropertyEditorModule& PropMod =
        FModuleManager::LoadModuleChecked<FPropertyEditorModule>("PropertyEditor");
    PropMod.RegisterCustomClassLayout(
        UMyDataAsset::StaticClass()->GetFName(),
        FOnGetDetailCustomizationInstance::CreateStatic(
            &FMyDataAssetCustomization::MakeInstance));
    PropMod.NotifyCustomizationModuleChanged();

    UToolMenus::RegisterStartupCallback(
        FSimpleMulticastDelegate::FDelegate::CreateRaw(
            this, &FMyGameEditorModule::RegisterMenus));
}

void FMyGameEditorModule::ShutdownModule()
{
    if (FModuleManager::Get().IsModuleLoaded("PropertyEditor"))
    {
        FModuleManager::GetModuleChecked<FPropertyEditorModule>("PropertyEditor")
            .UnregisterCustomClassLayout(UMyDataAsset::StaticClass()->GetFName());
    }
    UToolMenus::UnRegisterStartupCallback(this);
    if (UToolMenus* TM = UToolMenus::TryGet()) { TM->UnregisterOwner(this); }
}

Full boilerplate with asset type actions, editor modes, and factory: references/editor-module-setup.md

Editor Utility Widgets

UEditorUtilityWidget (from EditorUtilityWidget.h) extends UUserWidget for editor-only UMG panels. Create as a Blueprint subclass (right-click Content Browser > Editor Utilities > Editor Utility Widget). Run: right-click the widget asset > Run Editor Utility Widget. Or subclass in C++:

#pragma once
#include "EditorUtilityWidget.h"
#include "MyEditorUtilityWidget.generated.h"

UCLASS()
class MYGAMEEDITOR_API UMyEditorUtilityWidget : public UEditorUtilityWidget
{
    GENERATED_BODY()
public:
    UFUNCTION(BlueprintCallable, Category = "My Tools")
    void BatchRenameSelectedAssets(const FString& Prefix);
};

// .cpp
void UMyEditorUtilityWidget::BatchRenameSelectedAssets(const FString& Prefix)
{
    for (UObject* Asset : UEditorUtilityLibrary::GetSelectedAssets())
    {
        if (Asset)
        {
            const FString Src = Asset->GetOutermost()->GetName(); // e.g. /Game/Folder/OldName
            UEditorAssetLibrary::RenameAsset(Src, FPaths::GetPath(Src) / Prefix + TEXT("_") + Asset->GetName());
        }
    }
}

Key UEditorUtilityLibrary functions (from EditorUtilityLibrary.h):

Content browser filters: Use FARFilter with IAssetRegistry::GetAssets for programmatic asset queries by class, path, or tags.

Open a widget programmatically:

GEditor->GetEditorSubsystem<UEditorUtilitySubsystem>()
    ->SpawnAndRegisterTab(LoadObject<UEditorUtilityWidgetBlueprint>(
        nullptr, TEXT("/Game/EditorWidgets/BP_MyTool")));

Blutility: Scripted Actions

UAssetActionUtility — Asset Right-Click Actions

Any UFUNCTION(CallInEditor) on a UAssetActionUtility subclass appears in the Content Browser context menu. Set SupportedClasses in Class Defaults to filter by asset type.

#pragma once
#include "AssetActionUtility.h"   // Engine/Source/Editor/Blutility/Classes/AssetActionUtility.h
#include "MyAssetActionUtility.generated.h"

UCLASS()
class MYGAMEEDITOR_API UMyAssetActionUtility : public UAssetActionUtility
{
    GENERATED_BODY()
public:
    UFUNCTION(CallInEditor, Category = "My Tools")
    void SetTextureCompressionToUI()
    {
        for (UObject* Asset : UEditorUtilityLibrary::GetSelectedAssets())
        {
            if (UTexture2D* Tex = Cast<UTexture2D>(Asset))
            {
                Tex->CompressionSettings = TC_EditorIcon;
                Tex->MarkPackageDirty();
                Tex->PostEditChange();
            }
        }
    }
};

UActorActionUtility — Actor Right-Click Actions

Same pattern for level actors. Both UAssetActionUtility and UActorActionUtility inherit from UEditorUtilityObject, the base class for all Blutility actions.

Detail Customizations

Class Customization — IDetailCustomization

class FMyDataAssetCustomization : public IDetailCustomization
{
public:
    static TSharedRef<IDetailCustomization> MakeInstance();
    virtual void CustomizeDetails(IDetailLayoutBuilder& DetailBuilder) override;
    // Override the TSharedPtr overload too — store WeakBuilder for async ForceRefreshDetails
    virtual void CustomizeDetails(const TSharedPtr<IDetailLayoutBuilder>& DetailBuilder) override;
private:
    TWeakPtr<IDetailLayoutBuilder> WeakBuilder;
};
// In CustomizeDetails: EditCategory, AddProperty, AddCustomRow, HideCategory
// Register: PropMod.RegisterCustomClassLayout(UMyClass::StaticClass()->GetFName(), ...MakeInstance)
// Unregister in ShutdownModule: PropMod.UnregisterCustomClassLayout(...)

Struct Customization — IPropertyTypeCustomization

class FMyStructCustomization : public IPropertyTypeCustomization
{
public:
    static TSharedRef<IPropertyTypeCustomization> MakeInstance();
    virtual void CustomizeHeader(TSharedRef<IPropertyHandle> Handle,
        FDetailWidgetRow& HeaderRow, IPropertyTypeCustomizationUtils& Utils) override;
    virtual void CustomizeChildren(TSharedRef<IPropertyHandle> Handle,
        IDetailChildrenBuilder& ChildBuilder, IPropertyTypeCustomizationUtils& Utils) override;
};
// Register: PropMod.RegisterCustomPropertyTypeLayout(FMyStruct::StaticStruct()->GetFName(), ...MakeInstance)

Full implementations, Slate row patterns, IPropertyHandle read/write, NameContent/ValueContent: references/detail-customization-patterns.md

Custom Editor Modes

FEdMode (from EdMode.h) provides specialized viewport interaction. Register globally; only one active per viewport at a time.

// MyEditorMode.h
class FMyEditorMode : public FEdMode
{
public:
    static const FEditorModeID EM_MyMode;
    FMyEditorMode();
    virtual void Enter() override;