How can I smooth this polysurface?

[Julius4 (Julius)]

Hello dear Rhino community! I have created a polysurface that is curved in three dimensions, similar to a ribbon. Unfortunately, it has some creases/edges in certain areas that I would like to smooth out. All my attempts to do this have failed so far, which is why I am reaching out to you to gather new ideas and approaches.

Thank you in advance and best regards!
240726_test.3dm (3.3 MB)

[martinsiegrist]

Rebuilding the two long boundaries of the strip helps.

With Sweep2 you can add a couple of slashes before and after the bends.

240726_test_rebuild_curves.3dm (239.6 KB)