I don't know if this is comparable, but I use Metapost for drawing graphs and diagrams. Actually, I draw diagrams long-hand on graph paper, with coordinates labeled, and code it up in Metapost. Even my 3D diagrams look really nice. The EPS output is scalable and can be included directly in TeX (or LaTeX) documents.
People tell me drawing diagrams long-hand first is too much trouble, but it really is the "secret sauce" for me. Also, Metapost is incredibly powerful once you dig in. I think it is ideal for technical drawings. The language is simple and powerful.