distorded sweeped surface (part WB)

[mwlandolsi]

Hello every body,
I need your help to produce this surface by sweeping a arc through an spline to get a surface like this

Screenshot from 2021-04-17 00-59-03.png (141.54 KiB) Viewed 353 times

Screenshot from 2021-04-17 00-59-36.png (141.22 KiB) Viewed 353 times

but i need a tighter closed path. so when i reduce the path opening, i got this :

Screenshot from 2021-04-17 01-00-00.png (193.5 KiB) Viewed 353 times

(the problem has nothing to do with linkstage3 or freecad official, it remains in both versions)
OS: Linux Mint 19.3 (X-Cinnamon/cinnamon)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 2021.412.22506 +5327 (Git) AppImage
Build type: Release
Branch: LinkDaily
Hash: d41e78fe7f9b54eea5977df0a7344331f08445e8
Python version: 3.8.8
Qt version: 5.12.9
Coin version: 4.0.1
OCC version: 7.4.0
Locale: English/United States (en_US)

[chrisb]

You may need additional sections for more guidance. Note that it is very tricky to get the sweep smooth then.

[Vincent B]

I don't understand why sweep carry out a such surface. But pipeshell (curves wb) works nice with yours sketches.

[mwlandolsi]

many thanks for your proposal.