By Eva Zimmermann
Three-dimensional printing is one of the most talked-about technologies of this decade. Some consider it the beginning of the third industrial revolution, while others point out the constraints of the technique. Is 3D printing changing our architecture, and is it the way we'll design our homes in the future? Below, we look at the phenomenon of 3D printing worldwide, including a delicate resin pavilion in China, classical-design-inspired concrete beams in Italy and buildings that "think" in Germany.

What is 3D printing?

The technology of 3D printing was invented by Chuck Hull, an American engineer. He initially called the new process stereolithography and patented it in 1986. The technique links molecules using laser light to form polymers into solid shapes.

Initially, industries such as automotive manufacturing used the technology for what became known as rapid prototyping. The advantage was that no molds were required and there was no waste, unlike in milling, where a shape is cut and the material around it is discarded. In 3D printing, objects are constructed layer by layer. The idea stems from printing with ink; in that process, the ink lies on top of the paper. If the process was repeated time and again, but with more solid materials and a slight shift to create movements in the layers, a 3D printing effect would occur.

Materials used in 3D printing range from the more common synthetic resins and plastics to steel and concrete. Some are experimenting with natural materials such as bamboo, wood and natural stone waste. Small versions of 3D printers are finding their way into designers' studios, schools and private homes.

But some synthetic materials used for printing are suspected of emitting toxins. In the course of an experiment, a doctoral student at the University of California at Riverside found that her zebra fish were dying in the container she had printed. A research team then tested the products of two of the most common 3D printers and discovered that the toxicity levels of both were quite alarming. Researchers worldwide are working to find safe materials and techniques and caution that the printers should be used in well-ventilated places.

Taking 3D printing to extremes in China

In China, superlatives represent progress, so it should come as no surprise that the largest printed architectural object was created there. Vulcan, a pavilion seen here, was revealed to visitors from all over the world during Beijing Design Week 2015. It was designed by architects Xu Feng and Yu Lei. But it was not printed all in one piece. Its curved form — 27 feet (8.2 meters) long and 9.4 feet (2.9 meters) high — was assembled from 1,023 individual components, all produced by a printer.

Although this achievement was rewarded with an entry in Guinness World Records, it also shows the limits of today's 3D printing technology: To print entire houses, the printers would have to be gigantic or run on huge scaffolds. Scale is the reason 3D printing is still in its infancy where architecture is concerned.

A full house in the Netherlands

In Amsterdam, though, DUS Architects is in the process of printing a canal house, layer by layer, using bioplastics made from 80 percent vegetable oil. The project, which aims to be renewable and sustainable, is slated for completion in 2017.

"There are also houses being printed in China," says Jane Burry, associate professor at the Spatial Information Architecture Laboratory at RMIT in Melbourne, Australia, "though [they are] relatively crude at this stage." She is referring to a project by Chinese company Winsun, which has printed houses made from concrete and recycled construction materials in China. It's one of the most cited examples of the technology in this context. The manufacturer reports considerable savings: 60 percent less material, 70 percent less time and 80 percent less labor compared with average house construction. The printer is set up in a factory and has gigantic proportions: 20 feet (6.1 meters) tall, 33 feet (10.1 meters) wide and 132 feet (40.2 meters) long.

Raising questions

"The question is how you define 3D printing," says Benedikt Hotze, media and communications consultant for the Bund Deutscher Architekten (Association of German Architects). When it comes to 3D printing in architecture, he is less than euphoric. "The idea to print houses all in one go is a childish fantasy; it's not going to happen," he says. "What will happen, however, is that we will have digitally controlled manufacturing of building components in a factory that will then be transported to the construction site. The often-cited examples from China seem to me to be excesses in the competition for the most attention."

Says Burry of RMIT: "The true strength of printing is for custom design and variety rather than mass production. So at RMIT we're looking closely at metal printing and how optimized structural node designs can be custom-printed for certain points in the structure of a building. By reducing the materials in the node, you can reduce the weight and substructure to support the building and save energy. This is a huge advantage of 3D printing, as it can be very costly to produce these structures by other means, such as casting, and you could even print one-off pieces for repair and restoration work."

Hotze regards the enthusiasm for printed houses with a pragmatic eye. "It reminds me of manned space travel — it's doable but not necessary. To this day, Omega creates the advertising for its Speedmaster watch around the fact that it was on the moon."

British architecture firm Foster + Partners, together with the European Space Agency, might disagree with Hotze about moon travel: It's developing ideas for 3D-printing a lunar base station for a project called Lunar Habitation, which could be completed as early as 2024.

Back on Earth

Though not quite as ambitious as the moon base project, a bridge construction project in Amsterdam, on which designer Joris Laarman is collaborating with MX3D, a developer of steel printers, and CAD developer Autodesk, is certainly prestigious.

Even though this image suggests the steel bridge is being constructed on-site at the Oudezijds Achterburgwal canal, it is really being manufactured inside a hall. The bridge has been printing at MX3D since fall 2015. The creators are attempting, by trial and error, to find ways to print the structure all in one piece. Printing is scheduled to be completed by 2017. That's when the first fully functional 3D-printed steel bridge is to be installed on-site — another race for a world record.

This little sample reflects what the entire bridge will look like. Two advantages of printing steel are that the shapes can be more organic and free-flowing than in normal production and molds aren't needed, which reduces the cost.

Printing concrete in Italy

In a collaboration between the University of Naples and cutting-edge technology company WASP (World's Advanced Saving Project), the beauty of Italian architecture is meeting modular building techniques.

WASP, founded in 2012 by Italian entrepreneur Massimo Moretti, pushes sustainable construction methods and in-house fabrication processes. With the University of Naples, it has developed a concrete support that could be made on a 3D printer and used in building projects.

Domenico Asprone, pictured above, assistant professor at the department of structural engineering at the University of Naples, was the construction engineer for the project. "Our idea is to print a curved concrete beam, optimizing the amount of concrete and reducing the costs for complex formwork systems," he says. "The approach is based on the partition of the beam into concrete segments to be printed separately, and then assembled into a unique monolithic element, along with the steel reinforcement system, as in a Lego structure. The approach is expected to facilitate the production of curved elements with variable cross-sections, compared with the common concrete casting process, and will therefore boost the creativity of structural engineers."

"The beam is printed in individual pieces," Asprone says. "Once the concrete pieces are hardened, reinforcing steel bars [rebar] are externally installed to strengthen the beam and lock the pieces into a monolithic element."

The WASP experts have already printed a reinforced concrete beam about 10 feet (3 meters) long. For this purpose, they used a lower-viscosity concrete. "We are standing on the shoulders of more than one century of concrete technology history," Asprone says. "We are merely adapting this technology to 3D printing. We use cement and other binders, such as eco-friendly, clay-based versions or geopolymers that are waterproof and can be used for wastewater systems."

The next step for WASP? There are plans to print a pedestrian bridge similar to the one Laarman is working on in the Netherlands, but this one would be made of concrete.

Ornamental details in Russia

Russian manufacturer Specavia likewise uses 3D concrete printers in the construction industry, with most of its clients building contractors. Chief Executive Alexander Maslov describes the complex components his printers are already able to create:

"The 06044 series printers can print individual building components with a length of up to [40 feet, or 12.2 meters]. It's quite sufficient for printing complex shapes for all kinds of towers, arches, dwarf partitions and other decorative elements for a house. We've been printing various decorative landscaping elements, even a small pond and a children's town. The printer can be used for printing stoves, fireplaces, barbecue sets and other fireproof products using kaolin mixes."

From a technical standpoint, Maslov says, it would be possible to print entire houses, but he remains pragmatic. "Obviously, we're talking about printing individual components and assembling them on-site. The advantage of such a method is that you can do the manufacturing indoors, eliminating changes in temperature, humidity, etc. The disadvantages are cost of transportation and increased construction times. Plus, assembling the individual items is a technological process that requires further reinforcement solutions."

Still, Maslov believes that building techniques like the ones he's using will be integrated into regular construction within a few years.

An innovative take on the future in Germany

Professor Achim Menges, head of the renowned Institute for Computational Design at Stuttgart University, knows that innovation is an invitation to leave behind old thought patterns. "First you use the new technology to build objects in the traditional way, as demonstrated by the example from China, where they are building conventional houses with 3D printers," he says. "Designs and constructions that are genuinely specific to the new process are not created until the second step."

This means, for example, that "3D printing will make geometric complexity in building construction possible without much additional effort or expense. This knowledge in turn informs the design process," Menges says. Just as developments in software changed the aesthetic of architecture, so could 3D printing.

Because the technology creates components with multiple layers, "we will have the possibility of creating very complex building components with gradient characteristics," Menges says. "Components could be soft on one end and hard on the other due to different printing materials being used in the course of the printing with a multi-material printer."

3D 8: Bio-Inspired 3D Systems, original photo on Houzz

Buildings that can think?

Menges is working to create building components that can change shape, mirroring nature. "Just think of pine cones," he says. "When they are on the tree, their scales are closed. Once they fall to the ground and dry up, the scales open. We can imitate this effect with 3D printing by using different materials, soft and hard, that react differently to environmental conditions such as humidity. In this way, we can fabricate building components that adjust to climate changes without the need for mechanical or digital control mechanisms." The picture above shows such a prototype.

Some are taking this idea a step further. "There is talk about Industry 4.0, which is equivalent to a fourth industrial revolution," Menges says, "an interpenetration of the material and the digital world by means of so called cyber-physical systems." These connect software with mechanical and electronic components via a data infrastructure like the Internet. (The catchphrase is the Internet of Things.) This sort of building technology would change our daily world and the way we live completely.

Euphoria or caution?

Fans of the new technology put us on the threshold of a new era. If the technology is shared and becomes accessible to everyone — what's known as open hardware — 3D printing could potentially change the world. Product fabrication could move into the living room, and there would be less pollution because of the reduced need for transportation of goods.

But where architecture is concerned, the size of the projects remains an obstacle and the materials needed for such printing are still being developed. Safety issues also need to be addressed.

Burry proposes another competitor for the building construction industry. "I imagine 3D printing coming in parallel with other technologies in the next 10 years, but I would put my money on solid timber construction as the next big trend," she says. Cross-laminated timber is like plywood on steroids, Burry says, a bit like concrete in that it can be used to build the entire structure of a house in slab form, rather than having to build an internal frame. This means homes can be built faster and potentially cheaper. "That's not to say these technologies can't progress in parallel," she says. "Indeed, we can even 3D-print with timber-based material."

Much remains to be explored. We might not be 3D-printing homes on the moon anytime soon, but the technology will make more complex geometries possible, with building components that can adapt to climate changes and others assembled in a variety of materials. We can't wait to see what the next development will be.

Related reading:
5 Reasons Why We Need 3D Design
Why Concrete Countertops are Nearly Indestructible
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