For evaluating quality of free-form surfaces and visualizing their features, various curves on a surface, which characterize its properties, are defined and their equations are deduced. Newly introduced curves include those ...

This paper describes methods of c o n s t r u c t i n g s u r f a c e patches which s a t i s f y independently given boundary conditions on a l l i t s four or t h r e e s i d e s . A patch c o n s i s t s of two p a r t ...