LOS ANGELES, Calif. -

It isn't your average desktop printer. Imagine a 3D printer that can build a body part, a house, even a gun.
 
"It is building objects in a layer wise fashion, building things layer by layer," said Behrokh Khoshnevis, a USC professor of industrial and systerms engineering who has been experimenting with 3D printing technology for nearly two decades.

To understand how the revolutionary technology works, think of an inkjet printer that shoots miniscule droplets of ink onto paper. A 3D printer deposits droplets of plastic or other material and builds an object from the ground up.

"The decision has been to break down the 3D problem into a bunch of 2D problems, and then every layer basically can be much easier produced with a computerized method," Khoshnevis said.

Perhaps the largest advantage of these printers: the speed. Khoshnevis used a 3D printer to print our station's call letters, KESQ, in just five minutes. But he's gaining attention worldwide for creating a 3D printer that can build a 2,500 square foot home in just 20 hours.

"The only thing we've ever built layer by layer, and we have built it for thousands of years in that way, are these buildings," Khoshnevis said.

The massive printer, worth around half a million dollars, lays concrete and interlocking steel bars to frame the structure. It can build a multi-story custom home equipped with the infrastructure for plumbing and electrical work. Khoshnevis hopes the technology can help people all over the world.

"I really think the main potential economically is going to be in construction," Khoshnevis said of 3D printing.

But that's not the only industry taking advantage of 3D printing's precision and efficiency. 

"What 3D printing will allow in medicine is individualization and customization of patient care," said Dr. Raj Sinja, an orthopedic surgeon and president of Star Orthopedics in La Quinta.

Sinha is among the first surgeons in the country to use 3D printed surgical guides for knee implants. The guides are custom made to match the patient's anatomy. They allow the surgeon to make subtle cuts to the bone so that the implant fits properly.

"We can take the technology of CT scans, model the patient's own anatomy and build a device specific to them. So it's no longer a compromise of size or shape or fit," Sinha said.

Jean Hopkins of Palm Desert had two knee replacements in the last two years. One was done using traditionally-manufactured guides, which only come in a few sizes. The other was done using 3Dprinted guides shaped to fit only her.

"My custom knee, my right knee, feels more like my knee. The other knee feels slightly wooden, you might say stiff.  It doesn't have the same ease of movement that the right knee does," Hopkins said.

"She told me this was a totally different recovery. It feels natural, I'm not using my cane already at one month," Sinha said.

In the future, Sinha says the entire implant will be made by 3D printing. As will other human body parts.

The technology will also expand to consumers.

"There will be local 3D print shops or on the internet there will be numerous services where you can upload your design and then they build it and ship it to you," Khoshnevis said.

Soon individuals may even be able to buy their own 3D printers. But there are questions about the types of things people could build at home.

"Everything that you're looking at, basically, could be made with a 3D printer," Sinha said.

That includes weapons. A popular Youtube video demonstrates the first handgun built by a 3D printer. The potential implications are troubling, especially when it comes to regulation. 
 
"They're not going to be very sophisticated guns, but if you want to have something that fires and hurts someone you can do it very simply," Khoshnevis said.

As with all new technologies, 3D printing carries risks as well as benefits. But its unlimited potential could shape the way we build our future.