<i>Yeah I think they work differently in general. From my experience they do not benefit from iterative development the same way we do. They do but they iterate when solving the problem, usually on paper.</i><p>Yup, I've seen it too, from my experience.  I was once writing some desktop engineering apps, to help mechanical engineers / designers do analysis on materials etc.  They spend enormous amount of time doing iterations/studies on paper.  It is worth it, because it usually saves lots of money and time down the road.  They don't have the luxury that software developers have.