Center line between two curves on a surface

what command do you use if you have two curves and a sur
curve in center.3dm (885.3 KB)
face and you want to find the common center line between the two lines that fall on the surface? here is the example. thank you

in your case you can use ExtractIsocurve in V direction with snaps set to midpoint.

curve in center 2.3dm (7.2 MB)
what about something like this?

tweencurves for each pair of segments
join the created curves
pull the curevs on the surface
curve in center 2re.3dm (7.3 MB)