Lighting (4.26)

In a basic level the intensity of a directional light by default is in LUX. However if you reference that directional light in a blueprint and try and change the intensity there, with set intensity, a float is used. Is there any way to correlate the LUX value to relevant float value to return it to the original value after any changes made eg a fade?

Isn’t the intensity still in LUX?

From DirectionalLightComponentDetails.cpp:

void FDirectionalLightComponentDetails::CustomizeDetails( IDetailLayoutBuilder& DetailBuilder )
	// Grab the Mobility property from SceneComponent
	MobilityProperty = DetailBuilder.GetProperty("Mobility", USceneComponent::StaticClass());

	// Get cascaded shadow map category
	IDetailCategoryBuilder& ShadowMapCategory = DetailBuilder.EditCategory("CascadedShadowMaps", FText::GetEmpty(), ECategoryPriority::Default );

	// Add DynamicShadowDistanceMovableLight
	TSharedPtr<IPropertyHandle> MovableShadowRadiusProperty = DetailBuilder.GetProperty("DynamicShadowDistanceMovableLight");
	ShadowMapCategory.AddProperty( MovableShadowRadiusProperty)
		.IsEnabled( TAttribute<bool>( this, &FDirectionalLightComponentDetails::IsLightMovable ) );

	// Add DynamicShadowDistanceStationaryLight
	TSharedPtr<IPropertyHandle> StationaryShadowRadiusProperty = DetailBuilder.GetProperty("DynamicShadowDistanceStationaryLight");
	ShadowMapCategory.AddProperty( StationaryShadowRadiusProperty)
		.IsEnabled( TAttribute<bool>( this, &FDirectionalLightComponentDetails::IsLightStationary ) );

	TSharedPtr<IPropertyHandle> LightIntensityProperty = DetailBuilder.GetProperty("Intensity", ULightComponentBase::StaticClass());
	// Point lights need to override the ui min and max for units of lumens, so we have to undo that
	LightIntensityProperty->SetInstanceMetaData("SliderExponent", TEXT("2.0f"));
	LightIntensityProperty->SetInstanceMetaData("Units", TEXT("lux"));
	LightIntensityProperty->SetToolTipText(LOCTEXT("DirectionalLightIntensityToolTipText", "Maximum illumination from the light in lux"));


Some light sources are Lumen, Directional Lights are LUX (1 lumen / m2) which is still the Intensity property.

Not when you are working in blueprints:

The same light in the outliner is:
So the simple question is what intensity value would match the original LUX value.