_EdgeSrf from 3 curves

When making _EdgeSrf from 3 curves, on one corner the control points are stacked.
I want this point at a certain corner.

2023-03-10_EdgeSrf.3dm (31.5 KB)

This point seems random to me.
I want to understand the logic.
Up to now I have to try over and over until I get it as wanted.

In a couple of quick tests here, if you pick the curves one-by-one, it puts the singularity at the joint between curves two and three.

If you window select, it seems that it looks at the “age” of the three curves, the singularity is at the joint between two and three again, curve one being the oldest and curve three being the newest.


Between two and three…

I didn’t notice this logic.
Tricky, isn’t it?
Not very intuitive, but once known, one can live with it.

Thanks Mitch!

No, I don’t really know how it can be made so… It seems to be just calling some Sweep2 code behind the scenes, the first curve being automatically designated the “profile” and the second two the “rails”…