Hi, I’m making a world that is generated randomly and I can edit it from the game (something like a sandbox) but I have a problem I can not find how I can make a realistic mountain that do not look square where I can reach and make a small hole for hiding or building underground.
can i do something like that? if yes how? thx
If you don’t even have the slightest clue, this project may be too ambitious for you.
Perhaps start with “in-game editable terrain”. That may be a good place to start for you to begin to truly appreciate the depth of what you desire. I’m sure you can find some tutorials out that get into the nitty gritty details. Dug this up with a quick Google search, I suggest you give it a good sifting. 
Also, this is not the right place (the Physics board) for what you’re asking. I would take this out to general game design, maybe people there will have enough wind in their bags to point you in a few more directions.
thx