1d surface from points or edges?

Hi

Ive created a parametrically controlled set of surfaces that sit on a series of vertical ribs.
My next step is to cut out the ribs so that the surfaces would 'sit' on them but i cant seem to achieve this at the moment.

My idea was to connect the surfaces (see pic: in green) together with a new surface which will trim the ribs down giving them stepped edges. I have isolated the points (pic2) but for some reason im unable to make a 1d surface out of them..

can anyone help me? Thank you