This might already be baked somewhere but here goes.
Modern 3D printers can make very complex shapes but the material they use is less than ideal for final use as they are usually some sort of soft plastic. Modify a 3D printer to use a printing material such as wax (or low melting point plastic) then complete the final product with metal using the age-old lost wax method of casting with molten metal.
3D software should find it a trifling task to include pour lines (terminology?) into the design so that there are no air bubbles. There ya go - a complicated shape designed and printed with a computer but made out of metal with a minimal amount of hand-shaping required.-- AusCan531, Nov 17 2013 Makers of printers for lost wax process http://www.solid-sc...mension-3d-printersSomeone who has baked his idea. [popbottle, Nov 17 2013] I'm afraid this one is WKTE at least in the circles where casting is a routine activity. Pretty sure I've heard of jewelers using it, and I know 3D printers are routinely used for mold patterns (both lost wax and two part mold types).-- MechE, Nov 17 2013 Your right it is baked, but not common and routine and cheap.
You can also electroplate metals onto the printed shapes. The resolution of the printer and how big a part they can make as well as speed seem to be the frontiers.
Damn, I know I put that wax someplace.-- popbottle, Nov 17 2013 I would argue that it is as common, proportionally, as 3D printing is with respect to machining in general.
It's an absolutely basic application of the technology, it's just that the technology is only just coming into widespread use.-- MechE, Nov 17 2013 WKTE but I was not privy. Will be deleted. Good link [popbottle].-- AusCan531, Nov 17 2013 I've also seen it done directly with some of the plastics used, particularly with PVC. The burnout temperatures are higher of course, but the process is the same.-- Freefall, Nov 20 2013 random, halfbakery