an exemple : my street level is above a basement so there is a ceiling height for the basement that is a little above the street level. But the "street level is on a concrete that is about 2" thick.
What may I enter as an "elevation" for my street level ? (I did tup - 1" and 1" ceiling thickness, is it correct ?)

Is it possible to have a floor thickness in the basement (only part of it have a concrete floor, with some thickness, but the level 0 have the thickness grayed, I cannot enter anything there)

Thanks