UScriptableInteractiveToolPropertySet is a Blueprintable extension of UInteractiveToolPropertySet. This is a helper type meant to be used with UScriptableInteractiveTool. The intention is that the "Settings" of a particular Tool are stored in UScriptableInteractiveToolPropertySet ("Property Set") instances. The function UScriptableInteractiveTool::AddPropertySetOfType can be used to create and attach a new Property Set. Then these settings can be automatically exposed by, for example, the Editor Mode UI, similar to (eg) Modeling Mode in the UE Editor.