I have the idea of making an underdark city for a Drow-theme campaing that I'm running, but the problem with City Designer is that all the buildings are human oriented, no stalagtites or something like that.
I was looking for a library of underdark, but I can't find it. So I was thinking in made my own, rock/stalagtites, or something like that, but I don't know how to do that.

Any Idea?