The base you have, you draw the top of the right odds, and then you make a nice loft...thanks for the answers.
in the image there is the scheme of the plant. I could extrude directly from the plant if it was a single body with the same height, and it is not...I try to explain myself better:
the narrow and long part is high type from 3 to 6 mt then turns and develops the real tall building at least 10-12mt. (I must make a rendering of a masterplan, therefore it is still all approximate).