If you take a look at the rapid prototyping design world, the processes and methods currently in use haven't changed a great deal since the Industrial Revolution. Metals are still machined from solid billets, cast in moulds, or stamped with dies. Plastic products are produced in much the same way, using
rapid prototyping design techniques.

Rapid prototyping design article

However they are sophisticated. Materials may have become more advanced, but much is still the same as when our medieval ancestors forged with iron and bronze. While productivity and efficiency has gone through the roof, allowing ever more units to be manufactured everyday than ever thought possible, it still doesn't change the fact that the underlying processes are still the same. If they wanted to produce his first Iron Bridge today, chances are he'd be using exactly the same methods. Like so much in today's technologically-focused world, many are looking to new technologies to provide new processes, and perhaps materials, so that we can move forward. But where is this next quantum leap going to come from? One answer is to extrapolate today's rapid prototyping technology, from where it's currently at (as an aid to the design and product development process) to the point where we manufacture and use the parts that these machine produce as production parts, rather than short term prototypes – hence the rapid prototyping design tagline.