How architectural models are created using additive manufacturing

Creating architectural models through additive manufacturing offers a fascinating blend of technology and design, transforming the way architectural concepts come to life. Take, for example, the Renzo Piano Building Workshop (RPBW), an iconic firm founded in 1981 by celebrated Pritzker Prize-winning architect Renzo Piano. With offices in Genoa, Italy, and Paris, France, this studio has become a global beacon of innovative architectural practices.

The workshop is steered by nine partners, including Piano himself, ensuring a seamless blend of vision and collaboration. RPBW is a dynamic hub of creativity and technical expertise, employing a talented team of around 110 architects and supported by a diverse group of 30 specialists. Among these are 3D visualization artists, skilled model makers, archivists, as well as dedicated administrative and secretarial staff, all working together to craft inspiring designs.

By integrating emerging technologies like additive manufacturing, RPBW can push the limits of traditional architectural modeling. This method allows for intricate details and precise creations that bring designs to life with remarkable accuracy. It’s a perfect harmony of art and science—a testament to how modern tools continue to shape the world of architecture.

RPBW has extensive experience working in multidisciplinary teams on construction projects in France, Italy and abroad. They have successfully completed over 140 projects worldwide.

As architects, teams are fully involved in projects from start to finish. They usually offer comprehensive architectural design services and consultancy services during the construction phase. Their design skills go beyond simple architectural services: their work also includes interior design services, urban planning and urban, landscape and exhibition design services.

Read on to find out Francesco Terranova AND Dimitri Langemodel makers from RPBW’s Genoa headquarters, on how they create complex architectural models using a combination of traditional tools and digital technologies such as 3D printing.

Design to build – design to build

RPBW’s focus is on «design to build», to ensure from the beginning that every detail works and represents the final building down to the smallest detail. For each project, hundreds of large and small models are created in the RPBW laboratories to test different proposals.

These templates are an essential part of architects’ workflow. They often meet around mockups of new projects to discuss different ideas for parts of the project.

«Sometimes the difference is very, very small. For example, one edge is smoother than the previous one. At the scale we’re working with, I don’t even know how I can see it,» Terranova said, smiling.

Architects often make changes directly to models, which they can then reproduce in CAD. Every few weeks, customers also come for a project update, where models play a crucial role, helping with the tangible update.

«Our models change every day or even every hour. Since architects change the design very quickly, most of the time we don’t have enough time to do it manually. So we have to find a way to do it faster,» Terranova said.

How scalar models are created

«Normally we start by printing the scale model on paper to understand the real dimensions of the model. If we have a model that is 1 meter by 1 meter, we need to understand how to divide it, because often, if the model is too bulky to be moved or transported, we have to consider building it already divided into two or more pieces, to be reassembled once it reaches its destination», explains Terranova.

Model makers use a combination of traditional tools for hand-made models and digital tools such as 3D printers, CNC milling machines, and laser cutting machines to create various parts.

«Most of the time, a model is made using all these technologies together. For example, for the base of the model, it is often better and less expensive to use CNC machine and hard materials. Some buildings are CNC milled and laser cut,» Terranova said.

“Sometimes we have geometries that are not easy to make by hand, for example spheres and curved surfaces. Making them by hand is almost impossible or you have to spend something like a week instead of a few hours. But if you 3D print it, of course you can make exactly what you see in the 3D file. We try to use 3D printers as much as possible to make our work easier.”

Model makers also use 3D printing for complex parts like ladders and trees that would take a long time to make by hand. For example, they 3D printed the complex column joints for the model of the new San-Giorgio motorway bridge in Genoa that recently replaced the Morandi bridge that collapsed two years ago.

Although architects use Autodesk Revit CAD software to create digital files, it cannot always be used to create physical models directly to scale.

«What they export is not ready for us. The buildings are complete: pipes, taps, furniture, etc. We don’t need these details on a scale model. So we have to clean up the file and we also have to consider the thicknesses we can use. For example, a wall 10 cm thick, on a scale of 1 to 200, becomes 0.2 mm. This doesn’t work on machines, so we have to manage the files and adapt the 3D model,» Terranova said.

Digital files for 3D printers must also have a closed volumetric surface. Some models can be fixed automatically, but model builders often have to redraw the entire model

Choosing the right technology for additive manufacturing

The Genoese studio received its first 3D printer six years ago. Since then, they have expanded their fleet to three cars, using three different technologies, and have tried many more.

“Six years ago, we started with a powder machine [care utilizează tehnologia de jet de liant]. It wasn’t very helpful because it was very sensitive to humidity and the accuracy wasn’t what I needed. So I moved on to Module 2, [care utilizează tehnologia de imprimare 3D stereolitografică (SLA)]. Then I added a 3D Systems [imprimantă cu jet de material de format mare] those who print with resin. And we also have a small FDM 3D printer that works with PLA and ABS,” Terranova said.

“What we really appreciate about Formlabs machines is the solidity and resistance of the material, as well as the precision of the models. Formlabs resins, once printed, are very easy to sand. This is a great thing, because we always have to paint the model. Even if we use white resin, the white is not exactly the same white that we use with our models. In fact, we have to paint the model made with 3D printers and also the rest of the model made with CNC machines and other tools. So it is so very useful for be able to grind it easily,” Mr. Terranova said.

“With the FDM 3D printer, we don’t have the same precision. We see all the layer lines and that’s not a good result for us. The 3D Systems printer is very precise and for large-scale architectural detail models (1:5, 1:10), it’s useful. But the material is not that solid after cleaning it. For example, if we 3D print trees with that machine, after half a day or less, the trees fall off. They look like they’re melting,” Mr. Terranova said.

Most recently, the studio upgraded their Form 2 with Formlabs’ latest Form 3 SLA printer, which allowed them to print some of their most complex designs while saving time in post-processing.

«The trees were a big problem because they are very fragile, very thin. We tried to do that with shape 2 [și celelalte imprimante, dar s-ar rupe]. With the Form 3 we don’t have the same problem and it allows us to 3D print trees. Removing supports with the Form 3 also seems easier because we can use smaller supports,” Terranova said.

The future of architectural practices

The Genoa studio recently relocated its Form2 3D printer to the New York headquarters, meaning that all three RPBW offices now employ 3D printers for modeling purposes. Both Terranova and Lange anticipate that utilizing digital tools will foster greater knowledge sharing across their offices. Terranova is confident that 3D printers will become indispensable in most architectural studios and laboratories in the near future. He believes this technology represents the future but acknowledges certain advancements are still needed to make it more accessible for all modelers. Lowering costs is one such hurdle, though companies like Formlabs have already made strides in that direction.