Surface from edge curves

Hi, can anyone explain the odd surface resulting from these two edges please…

edge (7.9 KB)

and yet it seems to have a clean extrude…

If you create a surface from two edges, you should ensure to create the same curve properties for both curves. If the curve property differs (cp count, parameterization, degree …) , the surface will be heavy. By watching your iso-curves, it is obvious that your surfaces are garbage. Ideally you only offset the lower-curved parts, then you rebuild and blend them. Sounds a bit of overcomplicating things, but if you want proper surfaces, this is the only way in doing it.

I understand that…thanks…what is odd is that “offset loose” produces a curve with 6 cp but “offset” produces 184 cp

Try is this

The curves are not internalized

the surface still has odd overlaps…yet also produces an accurate extrusion…it must be something to do with the closeness of the two curves…as I move them apart the overlap disappears…anyway, I had just wondered why the two offset components produced such differing numbers of cp’s

internalize the curve’s

or rebuild both the curves with same number of control points ad try it