Even the most well-conceived physical and computer analytical models can only approximate behavior and should complement simple hand calculations. If analysis is at best an approximation than some forms are easier to approximate than others. David Billington, when referring to the wide range of visually interesting shell forms that were generated by individuals who relied on and developed simple rather than complicated analysis techniques, notes that shells “carry forward the central scientific idea in structural art: the analyst of the form, being also the creator of the form, is free to change shapes so that complexity disappears.” [4] Here Billington does not mean that structures should only take on well-studied forms, but rather is emphasizing that engineers rely on experience to avoid unnecessary complications when creating new forms. Form-finding models like hanging chains and membranes and soap film take on rational forms and suggest how their full-scale equivalents will behave. These models may be of vastly different materials and scale than the final structure and therefore appear more like an abstraction than a facsimile. Engineers still need to exert judgment when assessing the validity of a form-finding technique, but the models are meant as a point of departure from which additional visual and analytical models are developed and used iteratively to inform the final design of a structure. Today, computational form-finding has replaced most physical form-finding and while physical form-finding is still informative as a means of developing intuition, physical modeling has a more direct benefit for the design of moveable and adaptable structures.
Physical models as complements to computer models have potential as visual, analytical, and design tools. At the small-scale one can generate and refine forms while approximating behavior. However, only at the full-scale can one make a proper aesthetic critique and confirm that the form safely carries the loads acting on it. For Isler, studying his completed works was an important part of his design process. Isler viewed each structure as an opportunity to reflect. This reflection is another form of discipline or striving to understand behavior and material constraints that informed his play or his future exploration of rational form. Today many of Isler’s shells like the BP Gas Station completed in 1968 and Bürgi Garden Center completed in 1971 are still used and are in excellent condition proving not only the success of these structures, but also the success of Isler’s process.
Isler, like other great structural artists relied on physical intuition gained from first-hand observation. Today most physical modeling has been replaced by computer modeling; however, computer modeling can compromise the development of one’s physical intuition. Because practitioners are more likely to use computer models than physical models, this physical intuition has to begin to be developed in college through the use of physical visual, analytical, and design models. Many institutes both abroad and in the United States already incorporate visual and analytical models into their curriculums, but more emphasis should be placed on creating design models as a means of generating more creative and rational forms and understanding the balance of discipline and play required to create efficient, economical, and elegant structures.
Student visits to built works and with practitioners should complement design exercises. In Europe, some practitioners are also full-time university faculty providing students with a mix of theory and practice in the classroom. However, in the United States while this is typical for architects it is not as common for engineers. As a result, universities in the United States usually emphasize theory and analysis rather than design. While this approach may teach students about fundamental structural behavior and how to analyze a particular set of members, it does not inspire creativity or elicit thinking about globally efficient forms. Visiting aesthetically pleasing built works and meeting with leading practitioners reassures aspiring engineers that the potential for new, visually interesting, and efficient forms exists. Physical models can help students and practitioners realize this potential.