Dear Fabrizio:
With all due respect for you and your team's hard work in Archiforma, I observe that while the skin you created to emulate my Zoom skin is similar in form, is it not true that you cannot edit each surface spline or node individually?
I admit that in practical terms, when a model isn't right from the beginning, doing the whole part over again is probably a safer course of action than to start pulling on nodes, but the strength of free-form modeling is just that - editing anything: anywhere, anytime. This is also an invitation to the blues as this type of modeling can get out of hand. Bolt your display down securely before starting with Zoom.
Zoom creates an active node at every polygonal mesh intersection allowing for finished form not derivative of the two originating polylines. ArchiForma - correct me if I am wrong - can only control the skin by editing the edge polylines......
I believe that most, if not all form we need in ArchiCAD can be created in ArchiForma - a fine product that I use all of the time - especially when making things that need to be tilted - a real time saver. But when modeling elements to be seen up close that must be photographically accurate, a NURBS modeler is appropriate.
With some analytical study of the object to be modeled, ArchiForma can make a fine approximation, but is limited in more extreme, non-geometric situations.
So in this case, the two-mints-in-one approach doesn't work - you need both modelers - ArchiForma for quick things in ArchiCAD and Zoom for sinuous, plastic, multi-curved, infinitely-editable surfaces.
Dwight Atkinson