What CAD program do people use and like? What programs use a standard data file format? It's ok if it requires me to pay. I have budget. But suggested good free programs are appreciated. What I am looking for is a CAD program to do 3D design of complicated parts. In particular, I am a nuclear safety guy, so I am looking to do design of various parts in a nuclear reactor. But also other things like fuel transfer equipment, handling bays, storage bays, etc. I'm hoping for a nice 3D view. Also, I am hoping to take the data out of the CAD program, manipulate it, and feed it into an analysis program. That is why I am hoping for a standard data file format that I can get the definition for, and write a program to extract the data.