by Thomas Seebohm, with B.J. Novitski
Rapid prototyping technologies such as 3D printers and stereolithography have achieved some popularity in producing architectural models. But these methods are limited in the size of the models they can produce, and they require expensive materials. So at School of Architecture at the University of Waterloo, we have been working with computer numerical control (CNC) milling to produce architectural models. We have demonstrated the utility of CNC machining by producing a 1:33 scale model of a curvilinear, precast-concrete structure for the Ballingdon Bridge in Suffolk County, England.
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Although most major structures are designed today with digital technologies, there are still times when a physical model is necessary. To understand a structure as complex and innovative as the Ballingdon Bridge, we wanted a physical model that we could hold in our hands.
In investigating techniques for creating physical models from digital data, we found limitations with other rapid prototyping technologies. For example, the largest 3D printer from ZCorp produces models of a maximum size of 20 by 24 by 16 inches (500 by 600 by 400 millimeters). While it is possible to produce larger models by assembling smaller pieces, this is cumbersome.
Another concern is the expense of materials. Producing a 40-inch (101-centimeter) model of the bridge with a 3D printer would have cost over $3000 (Canadian).
To produce larger, less expensive models, we purchased a three-axis CNC router from Techno-Isel with a 50- by 50-inch (127- by 127-centimeter) table and with a Z-axis travel of 6.5 inches (16.5 centimeters). The material cost of building the bridge model, using basswood, was less than $200.
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Ballingdon Bridge, Suffolk County, England, designed by Michael Stacey.
Photo: Brookes Stacey Randall Architects
3D Studio model of Ballingdon Bridge ready for export to Visual Mill.
Image: Jonathan Friedman
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