Design development - form-finding, patterning and pre-stress

5 Design development - form-finding, patterning and pre-stress 

Design development is an iterative process. Unlike the tents of old, modern tensile structures are normally expected to display a smooth, unwrinkled surface under all expected loading conditions and whilst, at times, undergoing substantial displacements. This requires accurate determination of the form precise patterning, cutting and assembly of the material detailing of 

3 Anticlastic surfaces (a) conic (b) saddle/ hypar (c) arch supported (d) wave form (photos John Chilton). 

Because of the nature of tensile surface structures it is not easy for the architect, designer or artist to visualise accurately the final form. The shape cannot be arbitrarily determined but is, in effect, self-determining. It results from several factors, over some of which the designer may have little or no control, for instance  

At the conceptual design stage, soap films (which are uniformly stressed tensile surfaces) developed within a combination of rigid (e.g. wire frame) and/or flexible (e.g. cotton thread) boundaries, may be used (Otto and 

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