User blog comment:Kacj321/The Elder Scrolls V: Skyrim Leaked/@comment-159.81.102.113-20111103083346/@comment-4074503-20111103175641

I think I remember reading somewhere where Bethesda announced that Fallout 4 would be using a brand new engine. I believe they said the Creation Engine, if I'm not wrong. So to add to the discussion :P Fallout: New Vegas is not considered "Fallout 4" :)