This is a post by Cat McClintock on PTC site.
With additive manufacturing (a.k.a. 3D printing), you design an object digitally and then send it to a 3D printer, which then builds it one thin layer of plastic at a time.
Sounds simple enough. But until recently, you had to use multiple software packages to get the model from your 3D CAD system to the printer. That meant you needed tools to export, redesign, optimize, and reimport your models. And worst of all, if you revised the model, you had to send it through all of these steps again.
Fortunately, newer developments in CAD software bridge the gap between 3D printing and 3D CAD. Now you can create and print your polymer objects, all within one environment—Creo.