I'm working on some procedural geometry stuff that requires I build lots of n-gons from intersecting curves, basically ribbon-like shapes that can overlap on themselves (e.g. a knot).
I'm running into an issue related to how a closed curve is filled (with a single n-gon).
Some configurations of curves fill as I'd hope and others require a reversing of the vertex order, and I don't get why.
I've attached a simple file that shows the issue: an intersecting curve will only fill in the intended way when reversed.
Can anyone explain why to me? It's kind of driving me crazy right now.
Thank you!
-Len

EDIT: There are other cases, with more complex “ribbons”, formed, essentially, of two offset curves (that overlap themselves at times), that will never form a clean face between them. They'll always form faces that fill larger loops rather than the ribbon space between curves. I figured if I created the geometry myself (in vex or python sop) that I could enforce the ribbon face simply by clean construction of points and vertices. But this doesn't seem to be the case and I'm trying to understand why.

No genius from SideFX has a genius thought on this one?