Both games are sandbox PvP MMOs in alpha tests, Camelot Unchained aka "Dark Age of Camelot 2" (...meets Minecraft, I would add) by Mark Jacobs and Crowfall aka "Game of Thrones meets EVE Online" - their very ambitious slogan from Kickstarter in March 2015.
This is quick intro to Camelot Unchained building, 100% free form - https://ello.co/jamesgoblin/post/lwcc9qkee_5xilkhpqhjma First images in it are from this video by Necromaniak, one of players in alpha tests:
In Crowfall, building is modular (you build from pre-made pieces like wall sections, towers...) but players will have tools to place rivers, mountains... at their own will (!) This is how it looks - https://ello.co/jamesgoblin/post/e6yhwdv6_xbjtdqnff1tma thou current player tests mostly focus on combat and (voxel) destruction of pre-made fortifications.
Some of it was taken from this video upate (it's rather long and kinda tech heavy):
...or 
