I heard about NURBS for the first time around 1995, when CADDS5
arrived in our office. And nobody understood anything to this E.T.
We used to work with Bezier patches and we were satisfied with them.
At this time, the "automatic" surfacers softwares were regarded by the big
chiefs as the tool of the future. So nobody get really interested in working with NURBS
In fact, our only contact with NURBS was the technical surfaces converted from CATIA. Each
part was made of hundreds of small patches, with thousands of CVs. Just good enough for
visualization or sections but no more.
It's probably the explanation of this legend saying "it's not possible to modify NURBS".
For several modelers, NURBS remains a controversial subject.
Even by now, many reject NURBS and only use Bezier patches.
The most common arguments are:
I use NURBS for 13 years now, and I can say it's a great tool, a big improvement of Bezier patches, one of the best features of ALIAS. A good use of NURBS ensure to work faster and cleaner.
When I arrived there, I discovered a sort of religion. For some modelers,
working with Bezier patches was something of a faith and a science.
Quality is the main focus of the A class modeler. Mastering the tool is necessary.
With experience, it's possible to "read" the shape of a curve or a surface just with
the structure of the CVs network. After years, it becomes like a instinct, a feeling that
leads the work. Just like the touch of a crafstman. And NURBS completely wiped this out!
With two or more spans, the CVs structure becomes completely different, "unreadable",
and the knots means nothing at first glance...