We expect the IBMs and Autodesks of the world to generate patents, but what about the smaller CAD companies. I looked for and found a few:
"Modeling three-dimensional objects on a computer system via a high bandwidth distributed network, facilitating the computing of intensive computer-aided design (CAD) tasks to take place on a series of servers." Patent number 6748419.
"...editing handles for solid shapes." Patent number 6781597.
Cadkey, Keycreator, Kubotek, Datacad, Graphisoft, VectorWorks
None. But some of these vendors might have patents in other countries.
Other smaller CAD companies, like Bentley Systems and CoCreate/HP, have a dozen or more patents.
Bonus: here is the flying machine patented by Orville Wright in 1903: patent number 821393. I wonder if the drawings are good enough to recreate the airplane?