Professor Kohler, as an expert on architecture and digital fabrication, what impresses you most about the institute’s new building?
This is the first time we have digitally prefabricated a roof of 2,308 square meters. A single robot autonomously performed every production step from cutting the spruce planks to assembling them. It’s something that has never been done before anywhere in the world.
What’s unusual about the sequential roof?
The free-form roof consists of 48,624 individual timber slats. They are all of different lengths and assembled at different angles to each other. It’s a degree of complexity that, unlike a human, a computer is well able to calculate. Our data model was implemented by Erne, a wood construction company in Laufenburg. They expanded their production plant site on the basis of our project and installed a gantry robot. This robot then manufactured 168 trussed girders, each 15 meters long. Finally, the roof was assembled at the Hönggerberg campus using conventional methods.
The combination of wood and digital technologies is not new to Switzerland. How is the sector developing?
Wood is proving itself to be an extremely effective and sustainable construction material in the digital age. We are exploring new potentials and looking to develop systems that will bring change to both construction processes and architecture. On the first floor of the institute building we have set up a 40 by 15 meter robotic lab for research in the field of architecture. which we call the Laboratory of the Future. From the air, four robotic arms can reach any point in the room where they construct something individually or collaboratively. They can quickly be retooled from wood to concrete or steel, meaning they can be used very flexibly for new processes all the time.
Does this have something to do with automation?
No, because that would be restricted to similar products. As architects we strive for open systems. Given our densely populated cities with their mix of old and new buildings, it is becoming ever more important to develop architecture for a specific place.
What questions are you wanting to pursue in the Laboratory of the Future?
Today, as the cities of the future are being built, it is important to make much more efficient use of materials. In this respect we are testing innovative construction systems. In the “Mesh Mould” project we even go a step beyond prefabrication. Here we are researching mesh structures that can be built directly at the construction site by robots and then filled with concrete. Whether straight, curved or double-curved: since these walls no longer need any formwork, they use less material. Concrete is responsible for the largest amount of CO2 emissions globally. Simply using walls of varying thickness shaped according to the flow of forces, can save a lot of concrete.
You are also director of the National Centre of Competence in Research (NCCR) Digital Fabrication. What synergies does this create?
In “Mesh Mould”, our professorship had the idea of the construction process. We were working with a first-generation construction robot. Then Jonas Buchli, Professor for Robotics, came to our aid and developed the robot further. Later the materials scientist Robert Flatt joined the team. And suddenly we have interdisciplinary teams combining their know-how to reach a common goal.
Back in 2005, you and Fabio Gramazio launched the world’s first robotics lab in the field of architecture at ETH Zurich.
Yes, and the international interest in the use of robotics in additive manufacturing of non-standard prefabricated components has since grown continually. In fact, there are now 50 such labs around the world. Whether at the Massachusetts Institute of Technology,
Harvard or at Stuttgart University: We are no longer the only ones, but we had a seminal influence at the start.
How is this young field of research doing at the moment?
We are an international community with an open research culture. Some of our know-how is protected, but most is made available to everyone else to help boost the ongoing development of the entire research field. With the NCCR we have an incredible number of visitors. Recently, for example, the CEO of WinSun came to see us. His company builds houses with 3D printers. It is one of the most exciting things currently happening industrially in China.
How soon could 3D-printers, robots and quadrocopters become a reality on construction sites?
Quadrocopters are fascinating but have a pretty limited payload. But next summer our robot is set to make its construction-site début on crawler-type undercarriages from the ETH Lab. It will be creating a free-form concrete wall by means of the new “Mesh Mould” construction technology at the
-NEST building in Dübendorf.
What is the vision that drives you?
We are working towards a digital construction culture. Architecture and residential space have hardly profited at all to date from all the digital developments. As an architect I am curious to see how our environment can be changed for the better through digital construction processes. I hope that this will lead to quality architecture, to better architecture.