=The system to build your own homes, combounds, hangouts from stuff you gather in the wasteland.
as described here on video : http://www.gamespot.com/articles/fallout-4-s-deep-customization-detailed-at-e3-2015/1100-6428095/?ftag=YHRe6a6b70
This looks so amazing to me! More than I could have dreamed you`d implement in game! Though it has been done/been possible lately to a large degree in mods for earlier Bethesda games, but putting it in the official game as such a "natural part" of the game, so smoothly, and, as it looks like in the preview, with such huge possibilities of what you can do : just amazing. Thankyou, very much looking forward to this, my favorite game developers once again !
Allways loved modding my own special home in Beth games or using other peoples mods to build stuff in game , but this looks like a real new era of building goodness !