Hi Michael,

Thanks for your quick reply. I can see your point about using a sub-d or brush-based tool. The thing is that the ribs are a bit more than just nice to look at features. They are really part of the wing and I would need to have them modelled and included into the 3dm file as the target is to generate stereo lithography masters. The real issue is not so much about making the ribs, but rather (as always with my woes with NURBS, like for wing transition into fuselage) to ensure seamless continuity.

This being said, I am starting to suspect that I have been making my life unnecessarily difficult. Judging from the first test pieces I got back from the maker, actual 1/350 scale STL objects do not display less-than-perfectly continuous surfaces in such a disturbing way as Flamingo or Modo renderings do, especially at 500+ magnification on a big screen. The matter is really to decide how much is good enough.

I had another stab at it this evening, trying to model a subset of the wing (the inner top surface), then blending with the edges that I had generated before. This works better (although I got mixed up with the alignment – having a wing generated in one go is way less fiddly, but as you say, such are the limits of NURBS).