One other tip - if you plan on thickening this shape up later, it may be better results doing that if your basic surface does not pinch together at the top and bottom - shelling and offseting surfaces tends to be sensitive to tips like this that collapse down to a single point.

If you want to make shelling work sometimes right now you will have to create a more rectangular base surface that is not pinched at the ends, and then trim it to make your curved outline.

That kind of non-pinched-at-the-tip underlying surface with a trimmed outline will tend to shell a lot more reliably.

- Michael

Thanks again for your helpfull answers...

Malc615 --> you have exactly what I was looking for. So, the only thing I had to do with my first attempt was to divide the main shape in 2, and use network tool.
So cool ! I can go on with the other parts

Michael :
"You can also use sweep for situations like this with 2 longer guide curves"
Yep,I tried it, it also works but I have less control on the volume...but it's usefull.

"For network it can be easiest to get a smooth object by doing the full object all at once instead of half."
That's what I was trying to do at the beginning, but it didn't work. Now, with the Malc615's advises it's OK.


(sorry if my english is not so good)

Post soon, when done !