When working on large scenes in Unreal Engine, it’s often helpful to highlight certain objects visually without altering their actual materials or geometry. For example, you might want to draw a red bounding box around meshes that have special metadata, making them easy to spot in the Editor viewport.

This is where FComponentVisualizer comes in. It’s an editor-only tool that lets you draw custom overlays for components directly in the viewport.

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Why Use FComponentVisualizer?

• Non-destructive: Doesn’t modify materials or assets.
• Editor-only: Perfect for debugging or visualization during level design.
• Lightweight: Draws simple lines or shapes without heavy rendering overhead.

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Step 1: Create a Visualizer Class

Start by creating a new editor module (or plugin) and add a class that inherits from FComponentVisualizer.

// MyStaticMeshComponentVisualizer.h

#include “ComponentVisualizer.h”

class FMyStaticMeshComponentVisualizer : public FComponentVisualizer

{

public:

    virtual void DrawVisualization(

        const UActorComponent Component,

        const FSceneView View,

        FPrimitiveDrawInterface* PDI

    ) override;

};

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Step 2: Implement the Drawing Logic

In the .cpp file, check if the component is a UStaticMeshComponent and whether it has your special tag. Then draw a red wireframe box around its bounds.

// MyStaticMeshComponentVisualizer.cpp

#include “MyStaticMeshComponentVisualizer.h”

#include “Components/StaticMeshComponent.h”

#include “Engine/EngineTypes.h”

static FName SpecialTag(TEXT(“Special”));

void FMyStaticMeshComponentVisualizer::DrawVisualization(

    const UActorComponent Component,

    const FSceneView View,

    FPrimitiveDrawInterface PDI)

{

    const UStaticMeshComponent SMC = Cast<UStaticMeshComponent>(Component);

    if (!SMC || !SMC->GetStaticMesh()) return;

    const bool IsSpecial = SMC->ComponentHasTag(SpecialTag) || SMC->GetOwner()->Tags.Contains(SpecialTag);

    if (!IsSpecial) return;

    const FLinearColor Red(1.f, 0.f, 0.f, 1.f);

    const FBoxSphereBounds Bounds = SMC->CalcBounds(SMC->GetComponentTransform());

    // Draw a red wire box around the mesh bounds

    DrawWireBox(PDI, Bounds.GetBox(), Red, SDPG_World);

}

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Step 3: Register the Visualizer

In your editor module’s StartupModule():

#include “UnrealEdGlobals.h”

#include “Editor/UnrealEdEngine.h”

#include “MyStaticMeshComponentVisualizer.h”

void FMyEditorModule::StartupModule()

{

    if (GUnrealEd)

    {

        TSharedPtr<FComponentVisualizer> Visualizer = MakeShareable(new FMyStaticMeshComponentVisualizer());

        GUnrealEd->RegisterComponentVisualizer(UStaticMeshComponent::StaticClass()->GetFName(), Visualizer);

        Visualizer->OnRegister();

    }

}

void FMyEditorModule::ShutdownModule()

{

    if (GUnrealEd)

    {

        GUnrealEd->UnregisterComponentVisualizer(UStaticMeshComponent::StaticClass()->GetFName());

    }

}

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Result

Now, any StaticMeshComponent tagged as "Special" will display a red bounding box in the editor viewport. This is perfect for debugging metadata-driven workflows without touching your game’s runtime visuals.

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Pro Tips

• You can draw more than just boxes: spheres, lines, or even mesh outlines using FPrimitiveDrawInterface.
• Combine this with UAssetUserData or custom metadata for a robust pipeline.
• Keep visualizers lightweight, they run every frame in the editor viewport.