Right. Profile 1/2 since it is revolving on itself. From the center.
Also:
be sure to make the profile to the upper right, with the revolving point in the lower left. This respects the specific hierarchy Archicad uses to interprt left/right and up/down, avoiding the annoying reverse and/or inverted profile.
Also:
Archicad won't revolve around nothing: always leave a tiny hole in the bottom of the revolve (by ofsetting the revolve a little) or you risk getting a false result....
Dwight Atkinson