Hi Riko, a few links to some previous sofa discussions here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3841.3

But yeah like Pilou shows you're probably going to want to make the section between each crease a different object and put in some kind of rounding between them.

Also that is kind of getting into the territory of the kind of model that can be better done with sub-d polygon modeling rather than NURBS modeling.

- Michael