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Digital Fabricators

An exhibition at the Architecture Pavilion at Interbuild, 'Digital Fabricators' explores the relationship between architecture, manufacturing techniques and digital technology.

The curator, Michael Stacey, sets out the key issues below. A selection of the case studies presented in the exhibition are described in detail on the following pages The landscape of every architect's office has changed over the past 20 years - gone is the gentle squeak of Rotring pen on Mylar or tracing paper to be replaced by the hum of computers and the intense clicking of mice. This change has been embraced by architects and engineers.

But two-dimensional drafting still dominates the construction industry and is used primarily for its flexibility and a hoped-for efficiency. The revolutionary potential of three-dimensional modelling is used fitfully and only by a few. This article, like the exhibition, explores the use of digital design to inform the built environment.

The emphasis is on experiential and tactile architecture, not the theoretical. The potency of the sketch and three-dimensional models is beyond doubt. But the communicative potential of digital design, in all stages of the design process from concept to direct communication with the fabricators, is still in its infancy in the construction industry.

The exhibition includes the timeline of the development of digital design and fabrication technology. For example, the introduction of AutoCAD in 1982 had a much swifter impact than the introduction of stereolithography in 1988. The projects illustrate the expanding diversity of digital fabricating techniques, from laser cutting to five-axis routing, and stereolithography to three-dimensional physical printing. The exhibition includes a taxonomy of current digital fabrication technology. Branko Kolarevic uses the following classifications of digital fabrication: two-dimensional, subtractive, additive and formative. Within each category there is a delta of possibilities, and many of the fundamental issues of tectonics in architecture, the joining of materials and components, remain unchanged by the use of digital fabrication. This is leading to a re-engagement with the means of production by the profession and a rediscovery of craft in architecture.

Some are concerned that rapid prototyping in particular lacks any sense of materiality;

however, Ulrika Karlsson of Servo notes that the layered topography of the stereolithography rapid prototypes of lattice archipelogics has it 'own and unique materiality, which is a direct result of the setting of the resin by exposure to laser light, layer by layer'. Laser cutting uses the nature of the chosen material directly - Philip Beesley and Diane Willow's Orpheus Filter is an accretive installation formed from laser-cut acrylic and Mylar film. Thus they are using the very film one used to draw on to create working drawings.

Parametric design The combination of parametric design and single project models offers the architect a potent real-time tool to generate options and iterate the design to access the potential within a conceptual approach. Parametrics define the parameters of a particular design and not its shape. This is a powerful new tool in form-finding for architecture.A parametric definition of a circle is r 2= x 2+ y 2and the parametric definition of the arch of Waterloo Station as defined by Robert Aish of Bentley Systems is hx = ((29152 + (B+C) 2)0.5). This is not to suggest that practices should all hire mathematicians, which Foster has done, nor that you should enrol for a maths degree. Thankfully, major software companies are developing visual interfaces or 'self-programming' for parametric design. The parametric capability within Bentley's Microstation suite is called 'generative components'.

The Swiss Re office building is a pioneering exemplar of parametric design. It takes the market preconception of an office layout and, through parametrics, transforms it into an optimal design where aesthetics emerge from performance criteria applied to design.

Francis Aish, an aerospace engineer by training and now an associate at Foster and Partners, describes this parametric process as 'two and half D' as the parametric qualities of the seven tangential arcs that form the profile were applied to the sectional geometry and related to the circular plan.

One does not need to be the architect for a regional arts centre or major office building to use parametric design. Urban Future Organization's design for a house conversion in London called Nested House V1.03 ably demonstrates this on a budget of under £60,000. It is also vital to remember that the development of digital design is about the investment in people - Gehry transformed his office by hiring Jim Glymph and Rick Smith. The realisation of Foster projects such as the GLA and Swiss Re is only possible because of the investment in key software skills, in people, by fabricators such as Wagner Biro and Schmidlin.

Foster versus Gehry In the use of software there is a strong contrast between the approach of Gehry and Foster. Gehry has adopted an approach inspired by Boeing and uses CATIA (computer aided three-dimensional interactive applications). Furthermore, it requires the complete supply chain to adopt this single software to ensure continuity and compatibility. Foster's approach on Swiss Re, however, was to seek a robust software that everyone had access to - Excel. The geometry of the project was communicated as an Excel spreadsheet and a method statement on how to 'generate' the geometry. The specialist subcontractors' resultant geometry was then inspected by Foster's design team and any divergence discussed and eliminated. Swiss Re also very excellently demonstrates the interaction of physical models, made by the architects, and their digital models, a flip-flop from the physical to digital and back again, until all the consequences of the geometry are fully understood.

It is salient to note that as soon as true depth is applied to a specific geometry, for example the straight line or ruled geometry of the hyperbolic paraboloid roofs of Richard Rogers Partnership's Antwerp Law Courts, a curvilinear geometry is encountered. This was resolved by the close collaboration of Avtar Lotay, the project architect, and the specialist timber fabricator Merk. On Swiss Re, Foster's design team resolved the geometry to clad it exclusively with flat triangular panels with the exception of the crowning double-curved rooflight at the apex of the tower.

When reviewing the progression from digital representation to digital fabrication, it is easy to overemphasise the importance of technology transfer from the aerospace and automotive industries. This is not to deny the importance of software such as CATIA - however, progress within the construction industry, which includes CIMsteel, should not be overlooked. It is also pertinent to note that CIMsteel was a European initiative, which has now been taken up in North America.

No other industry is willing to undertake the risk of putting its prototypes on street corners and then standing back for, say, 20 to 30 years to see what happens. The building industry at its best is capable of putting together flexible project teams with disparate skills in the pursuit of common project goals. The use of digital fabrication technology need not be part of a more corporate future - the dialogue with industry should be a two-way process.

The possibilities generated by the direct manufacture of digital designs are both an opportunity and a challenge to the architectural profession. The technology is accessible and cost-effective. The inventive skills and editorial judgement of architects are needed more than ever.

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