DDO looks amazing. And checking out their website I just read this:
“DDO fuses with tools such as UE4, 3ds Max, Unity, Modo, CryEngine and Toolbag 2. Streamline turnaround by texturing directly inside the engine of your project, with DDO staying right inside the app. And as long as your own engine has hot-reloading enabled, DDO will snap right into your tool.”
Having DDO integrated right into the UE4 enginge and viewing the results inside of it sounds like a way great to dial in very accurate materials