3D printing (desktop manufacturing or fabrication) isn't only limited to building small parts and products (from plastic, metal, circuit boards, etc.). It is also scaling up to take on bigger tasks, including the construction of houses and buildings. A very cool recent example comes from Enrico Dini, of Monolite UK LTD in London. He has developed a new 3D printer called D-Space that uses stereolithography that has the potential to print complete buildings. Here's an overview of the printing process he is using:

A layer of base material (sand, gravel, sludge, or dust) is applied.

A magnesium-based binding agent and fibers (nylon or glass) are "printed" onto the base material per the computer design (CAD) of the structure at 25 dpi.

The resulting "sandstone" is microcrystalline that's similar to marble and structurally equivalent to reinforced concrete.

The material hardens to full strength in hours, allowing a continuous printing process from the foundation to the top of the structure.

Early claims are that it can build buildings four times faster and at half the cost of conventional methods. It can even build buildings with curved surfaces. In short, as the building industry aligns with Moore's law, expect the costs to drop dramatically (particularly as open source variants emerge for the machine and the binding agent). Think: "printing" the structures that form the basis of resilient communities (small team + printer can support an entire community).