3D printing is the way of the future and Nokia clearly wants to be on board. In a nod to the whole maker community, Nokia has released some plain schematics for cases that can be printed at home. They probably aren't very cost effective right now, but it will allow users to more easily design custom cases and print them at home.
The schematics would allow anyone with a 3D printer to make a case for the Nokia Lumia 820. According to Nokia, "[we] have become the first major phone company to begin embracing the 3D printing community and its incredible potential, and continue to be the leading phone company in this exciting field."
This is just the beginning of the 3D printing revolution. Imagine being able to craft a case that was modeled to your hard. The future is here and the future is awesome.