Starting a DB Project

[Ruben E garcia]

Ok I am going a little crazy with the Edges:
I can not make the south part of the top to flush, everything else is making contact with the surface, and If I keep removing material from the whole top so the south part can touch, I am going to be removing a lot of material from the original top... I don't know what is wrong... I also notice that the top curve from west to east is not perfect should i be concern about that? u can see it the pictures ???