Hi Roman, so basically to do something like that in NURBS you've got to kind of decompose it into some broader surfaces, temporarily ignoring areas that have tight bends in them since those tight corners will come from fillets.

It can be difficult to handle shapes that do not have a very clear decomposition though, which seems to be the case for your shape here, particularly in this area of it:



The fillet-like piece kind of melting away and losing its distinctive shape in that area will probably be challenging - that type of shaping without a clear delineation of forms tends to be difficult to do in NURBS.

- Michael