A new approach for shell form finding combining numerical and physical design tools

This paper presents a new design methodology that uses physical hanging plaster models and digital scanning techniques to appraise thin shell shapes in the preliminary design phase of a building project. The paper is divided into three parts. The first part gives an overview of the use of physical models in the development of structurally efficient shell shapes. By discussing the work of Wren, Poleni, Gaudi (i.e. hanging chains and hanging net model), Ramaswamy (i.e. hanging textile formwork), Isler (i.e. polyester resin membrane model) and Belles (i.e. models based on homeostasis), we illustrate the advantages and shortcomings of the presented physical methods and suggest how these disadvantages could be overcome. The second part introduces the new design exploration methodology that consists of three phases: Phase i) the physical hanging plaster model making, Phase ii) the digitizing of the physically form found surface, and Phase iii) the appraisal of the shell surface in terms of stresses, deflections and buckling using commercially available finite element software SAP 2000. In part 3 the paper concludes, by discussing the successfulness of the presented methodology (most specifically in the context of shell shape design exploration) and makes suggestions for other domains of application such as pre-stressed technical textile systems.