obtain a solid starting from an open surface

[Alfonsoserino]

Hello. I am a newer of catia v5 I have a part of surface not flat and open. from this last I should get a solid to offset 0 from the surface. How can I do that?
wanting allego photo

 

[dalmott]

then give a function thickness to the sup?

 

[scalareale]

Hi you can send a photo, I can't take a look at what you mean
for open surface