A couple of months ago, Dutch architect Janjaap Ruijssenaars announced that he was building a curvy, loopy and for some reason, largely see-through building, to be made with the help of Enrico Dini’s D-Shape 3D printer. The project would cost up to 5 million euros ($6.4 million) and be completed in 2014.

Universe Architecture Janjaap Ruijssenaars’s twisty, loopy 3D-printed building.

Another group quickly piped up, declaring that a similar project they were working on would be done even faster and cheaper. London-based Softkill Design intends to fabricate a web-like building and what’s more, it says it will need just three weeks to print the structure—and only a single day to assemble it, which it plans to do at some point later this year.

Softkill Design Softkill Design’s web-like confection of a building.

This month, another Dutch company jumped into the fray. DUS Architects plans to use a 20-ft-tall 3D printer to build a house along an Amsterdam canal. It’s also going to do it by the end of the year. Take that, Ruijssenaars.

DUS Architects DUS Architects plan to use non-traditional 3D printing methods to build a traditional house along a canal in Amsterdam.

3d house-printing—it certainly sounds like a brilliant idea. Why bother hiring masons and carpenters and plumbers when you can buy a machine and print out your own abode? Goodbye, apartment blocks. Hello, homemade homes.

But what does this 3d house-printing actually mean? And if it’s so groovy, how come no one has done it yet?

How it works

Steven Keating, Mediated Matter Group A cast concrete sample detailing the resolution of the combined additive (3D printing) and subtractive (robotic milling) fabrication process being developed.

First, the basics: Simply put, 3D printing works through a process of layering. The printer reads a file, much as a deskjet would read an image, and then translates that into a physical object the way your printer spits out ink on a page—one strip at a time.

The “ink” in a 3D printer is a material—often plastic—that shoots out of a nozzle and onto a platform. If a printer is making a coffee mug, for instance, it will gradually layer up a ring until it reaches the top. You could call it a bottom-up process.

But you would never want to print a coffee mug, not even a silly one. For the moment, the cool thing about the technology is that it’s better suited to protoyping shapes rather than reproducing existing ones. Plus, gift shops the world over have shown us that novelty mugs are always a bad idea.

Say you were a design enthusiast, though, and wanted to make a chair in an unconventional form. With a 3D printer, that would cost the same to produce as the sort of vanilla chairs you pick up at Ikea. That’s because 3D printers don’t constrain the imagination with mundane restrictions like molds, human labor or cost. If you can dream it—and get a design for it—you can print it. It gives designers the freedom to imagine all sorts of kooky things in much the same way that advances in printing equipment freed graphic artists from the tyranny of movable type.

3D printing big things is a challenge

Steven Keating, Mediated Matter Group Printing with foam at MIT’s Media Lab. Note the low resolution layers.

Things get tricky when it comes to large-scale projects, such as houses. The most obvious problem is one of scale. Just as you cannot print a billboard on a laserjet that can, at most, accept A3 sheets, you can’t print a entire house on existing 3D printers.

Building a bigger printer is not the answer. A skyscraper would require a machine that is bigger than it. And as printers get bigger, there is a trade-off between resolution and speed, says Steven Keating, a graduate student who works on large-scale 3D printing with Neri Oxman, an architect, designer and academic in the Mediated Matter group of the Massachusetts Institute of Technology’s Media Lab.

Steven Keating, Mediated Matter Group A large-scale 3D printer at work.

“You’re printing in finite-size layers,” Keating tells Quartz. “Imagine doing it with toothpaste. The thickness of that toothpaste is basically the resolution of your product. Every time you make that layer smaller, thinner, you increase the time it takes.”

Ruijssenaars is getting around these problems by building in bits and then putting them together on-site. Keating and Oxman have something similar in mind for their own 3D-printed building project. Like Ruijssenaars, they will print shells to later be filled in with concrete on the inside and be sanded down to look finished on the outside.

Softkill disapproves of these methods, dismissing concrete-filled structures as impure applications of 3D printing. While its house will also be printed in parts and assembled later, the company says it will be entirely 3D-printed with a light, plastic material. Its web-like configuration will make it strong enough to bear loads.

Printing with swarms

Atif Javed and Steven Keating, Mediated Matter Group A computer rendering of a concept for distributed mobile 3D printing of formwork for a building. Here, multiple small robots can work together in a swarm fashion to additively fabricate structures much larger than themselves, similar to termite mound construction.

There are other ideas too. The MIT group is experimenting with fitting its printer on a truck to increase its footprint. It is also looking into using “swarms” of 3D printers to work on different bits of a structure.

Atif Javed and Steven Keating, Mediated Matter Group MIT’s printer bot prototype.

But if it’s so much trouble, why bother printing houses when building them with lumber or bricks and mortar has served humanity’s needs for hundreds of years? There are three key benefits. The first is that 3D printing is cheaper. As a design becomes more complex, the cost of 3D printing drops substantially relative to traditional building methods.

It is also safer for both the people building the houses and for those living in them. Structures with curves are stronger. Pillars with greater density towards their edges are sturdier. And fewer construction workers means fewer injuries and deaths (though it also means fewer jobs).

But perhaps the best part about 3D-printing houses is that it lets architects dream up all sorts of fantastic structures that would be either too difficult or too expensive to make with conventional methods. A 3D-printed house wouldn’t need to conform to our traditional ideas of what a home looks like (which makes DUS Architects’ design look rather unadventurous). Indeed, that would be to miss the point.

It’s what architects like Frank Gehry and Le Corbusier first imagined possible with concrete, except that 3D printing has the potential to be several orders of magnitude cheaper, easier and more efficient.