Detail: In the past, you used diagrams a lot as design instruments, like those that depict the airflow around a spaceship. What is new about “design models”?
Ben van Berkel: Today, there are almost unlimited possibilities for designing a building – plus computer programs that allow any form to be created. Nevertheless, in many cases designs look alike, instead of exploiting the potential for diversity. We believe this is attributable to the complexity of architecture. “Design models” are a means of breaking down this complexity and developing a disciplined way of working. Artists and fashion designers are a step ahead of us in developing design methods. They manage to be innovative by concentrating on one specific area and initially setting aside other aspects: for example, by focusing on colour in a fashion collection. Once you’ve settled on a theme like that, it’s not difficult to find the appropriate material to bring out the colour to greater effect. Or think of Andy Warhol, who adopted the printing technique of Roy Lichtenstein as his starting point and then created something entirely new and independent by overpainting it.

Detail: What does the digital revolution mean to you in terms of design strategies?
Ben van Berkel: It plays a really decisive role. With the aid of computer-supported design, we can radically evaluate the basic typologies that have evolved in building history and work with new ingredients. To understand that, one has to consider the ordering systems in use hitherto. The “ingredients” of modern architecture are columns, floor slabs and open glazed facades. The orthogonal grid or collage is a popular system. The new thing about designing with computers is that we no longer have to opt for a particular system. We can combine a number of principles to achieve far more complex results.

 Detail: Doesn’t this combination lead to all the same “blob” designs, though?
Ben van Berkel: Not if you always bear in mind what you’re doing with digital tools. For instance, it’s interesting that at the junction of two components, one can control the transition and achieve a flowing form. If you leave both elements more less as they are, you create a collage effect. With an ever greater degree of fusion, you get a hybrid. We illustrated this type of hybrid – in which the starting element remains perceptible, but where something entirely new is created – in the case of the “manimal”, a synthesis of man and animal.

Detail: How has the working process changed for you as a result of using computers?
Ben van Berkel: The whole traditionally linear planning process can be rethought. In the past, we said: “This is the sketch. That’s the model, and from the two we’ll prepare the working drawings.” Only ten years ago, we were working more or less along those lines. In the past five years, we have applied complex engineering technology to find out at an early stage to what extent we can mould a particular material. By entering various materials in our parametric 3D data model, we can anticipate the interaction between forces from the load-bearing structure and external influences. Only when we are certain of what is technically feasible in detail do we return to formal considerations. That’s a revolutionary development with enormous potential. If I want a sheet-metal facade with a double curvature, I have to consider in good time whether it should be shaped in the factory or on site, or whether I shall reinforce it with fibreglass. That way, facade elements can be made thinner. Using the computer, we investigate the limits of a material in the light of its technical properties. At the same time, we can consider innovative visual and haptic effects.

Detail: Does that mean there are no drawing pens or model-builders in your office?  
Ben van Berkel: We don’t start immediately on the computer. If you work exclusively on a PC, there’s a danger that your imaginative, creative potential won’t be exploited to the full, or will be misapplied. We move between the various media and apply experimental techniques, like fashion designers and composers of modern music. Usually we start in a quite playful way by imagining what would happen if the building were a ball, say. Or in the middle of the design process, I introduce a little diagram from a different context. We work a lot with metaphors, but physical models help us in all this – usually quite simple paper models that serve to illustrate an idea clearly. To test a design with various materials, we clothe the building in a number of different ways.

Detail: You could also apply various textures to the digital model. What are the advantages of physical models?  
Ben van Berkel: The great advantage of physical models is their visual clarity. They also give you a sense of scale, which is much less pronounced with digital models. We work with digital models as well, of course. When we built the Erasmus Bridge, we learned to appreciate this working method, which is borrowed from the engineers. Today, we use advanced engineering programs like Topsolid and even combine programs to achieve the best solution.

Detail: Do you work with virtual reality in your visualizations as well??  
Ben van Berkel: We have experimented in this direction. In Stuttgart, we are planning an office building for the Fraunhofer Society, in which the use of new digital presentation screens is to be investigated. We made many presentations of our project in a “cave” – an all-round projection in which the model is experienced in virtual reality. This is all very interesting, but one shouldn’t lose sight of the real goal. In many cases, the physically built spatial model can show even more. We have a large model-building workshop in the office. Only complex models for construction in rapid prototyping technology do we outsource.

Detail: Could a spatially complex building like the Mercedes Museum be created without the aid of the computer?  
Ben van Berkel: Quite honestly, I believe it would be possible, but not in the short time we had available. The clients created conditions under which we were able to work with the latest technical facilities. Since the entire mechanical services are integrated in the exposed concrete structures, every detail had to be agreed with the engineers and the respective firms. Last, but not least, all changes in the plans had to be sent immediately and reliably to up to 500 different parties involved in the project – and on some occasions we had up to 200 updates a day. We were able to convince the clients that in addition to the planning team, we needed five further persons alone to create and maintain the 3D data model. That costs a bit more, but these are the key positions for monitoring the entire planning process. In the case of the Mercedes Museum, we had an external specialist in the person of Arnold Walz, who constructed and maintained a 3D parametric model. In a project like the museum, the points of intersection between the planning and production data are of great importance.

Detail: What is the advantage of a parametric model?  
Ben van Berkel: A parametric model means that you’re not only able to define the position of various points in space, but also the relationship between them. In the case of the Mercedes Museum, almost none of the tetrapod columns are the same. We didn’t draw the columns individually, though; we defined the parameters for them in terms of their raking form, slenderness and load transmission. If the radius of the building is changed, for example – and thus the load transmission and position of the columns – one doesn’t have to draw and calculate all of them anew. They generate themselves within the given parameters. The handling of the initial model reduces the risk of mistakes and miscalculations. It also helps to save materials and makes the construction process controllable. We call this “digital sustainability”.

Detail: In view of the intensive use of the computer, do you need a new type of architect in your office? Tobias Wallisser, who supervised the Mercedes Museum project, is an acknowledged computer specialist?  
Ben van Berkel: Absolutely! In the 1990s, Tobias was one of the leading minds and a pioneer in this field; but things develop at an incredible speed. I once jokingly remarked to him that he belonged to the Maya generation, because we used to create our 3D models with the Maya computer program. Nowadays we used Topsolid, and most of our young assistants are computer freaks who work a great deal with scripting techniques and can modify programs. A lot of them studied at the Städel School in Frankfurt, where I teach together with the best programming specialists. During their studies, they undergo a period of practical training at UNStudio, before coming back to us after getting their diploma.

Detail: Do you draw on the computer yourself?  
Ben van Berkel: I’ve always been interested in design techniques and have been very open to this technology, even though I had a classical architectural training. I’m keen to know the latest techniques. About eight years ago, I began to teach myself the 3D Studio Max program. I know the principles, therefore. But I would not be in a position to sit at a keyboard and build a 3D model on my own. My role is more like that of the composer who directs the orchestra without being able to play all the instruments himself.

Detail: Since when have you been working with digital 3D models?
Ben van Berkel: I think we were at least among the first architectural offices to do this. It began with the Erasmus Bridge in 1992. The assistant who introduced the system at that time is still in the office. The engineers were delighted to be able to carry out their work on the basis of our coordinate model. Maybe the reason why we are so open to innovations in this field is because we began to work with these things at a very early date.