Does anyone understand why FlowAlongSrf appears not centered in this case?

Hi everyone, I can’t find out why the command FlowAlongSrf produce such an error in my file. My curves to flow are centered on the reference surface (i obtained this surface by unrolling the target surface), so why isn’t it centered on the target surface? Anyone an idea? Thanks for your help

FlowAlong Surface.3dm (68.2 KB)

Hello - the target surface is not symmetrical - see the isocurves, and control points? Rebuild that surface to maybe 6 points across and then try, or make a clean new arc and extrude it as the target.Note those solutions will not be exactly the same - in more complex cases the rebuild way may be better because the surface is more evenly parameterized than from a true arc, but here is does not make much difference.

FlowAlong Surface_PG.3dm (58.9 KB)


Big thanks Pascal! So simple as you say it…