Data conversion failed from Curve to Surface

Hi everyone,

I’m a MArch student and I’m very new to GH. I’m trying to make a paramentric object but this error came up and I couldnt figure out why. I was trying to convert these contours into surfaces so I could extrude them. I have attached my rhino file and GH. Much appreciated to anyone would help and thanks in advance!!

1.3dm (15.0 MB) (10.6 KB)

the error comes from the Curves not being Closed: it’s impossible to generate a Planar Surface from an open curve
in particular you can see the first and last curves are open:

Thank you inno! Is there a way that I can close or delete them (if that’s easier)?

the issue originates from the original section curves from which the Brep is generated not being planar:

if you project those curves on the XY planes used for sweeping, before the sweep even happens, everything works as expected: (15.4 KB)

Solved! Thank you so much inno!