Seems I need Rhino. As I've just bought Maxwell, that's not an option. lol. What - I got a money tree? ;) I'm gonna keep your suggestions in mind, though.
I use 3d_coat for shapes difficult to do in rhino40.
Then import the obj file in rhino.
Apply some meshplanes through the obj obect.
Then Mesh intesect to find the curves i need.
Then loft to reconstruct the shape in nurbs.