Hi Michael and BurrMan;

Thanks for the responses. What I bascally did, I creaed those curves via LineWeb Tool, Then I made a surface from them via network command, then I used the trim command to divide the surface.

Well I did another method as follow and it worked without moving the curves:

1. Create a loft surface between two curves
2. Create curves on the surface with LineWeb Tool in both dirction
3. Trim the surface with the LineWeb tool curves and worked like a charm. See Attachment

Two more question

How do you get to the flat command?
How do you offset a curve that is on a surface on the same surface? Does the offset command works only in XY plane?

Thanks again

Sharif