> Sorry I used the wrong term, I wanted a sharp edge where the edge start
> to change its direction to be vertical.

It depends on the particular method you're using for the construction - for Loft like I showed above I used the "Loft Style = Straight" option. For something like Network you would either make the network in 2 separate passes for the top and bottom sections, or you would make your network curves come to a sharp corner point on that spot.


> I think I can detach the shape in two part but what if I want to tweak how sharp the corner is?

Well, again it depends on the particular surface construction technique that you're using but typically the entire shape of the surface is defined by the shapes of the profile curves used to construct it, so if you want something that bends more sharply you make the curves that are used for it bend more sharply and so forth...


With NURBS modeling you usually put most of the effort into arranging the curves, then the surfaces are constructed to follow that curve structure. You don't typically try to tweak a surface after it's been created - you usually try to get your curves set up so that the surface gets created with the desired shape right in its construction...


- Michael