surface.3dm (229.6 KB)
sorry, I was in a hurry to leave and I somehow changed the extension of the file
You must understand that your curves have to be separated as a rectangular grid, they need to be like a net. the curves in one direction are the U and in the other direction are the V
kind of like the image below
That’s why I cut your perimetric curve in four, (two U’s -first and last- and two V’s -again first and last)
you can put the line you are talking about, but you have to transform it so that it starts and finishes either on U or V, you cannot start from V and finish in U this is ‘illegal’ You cannot have triangles…
I hope i made you understand.