A parametric strategy for free-form glass structures using quadrilateral planar facets

The design and construction of free-form glass roofing structures is generally accomplished through the use of either planar triangular glass facets or curved (formed) glass panes. This paper describes ongoing research on the constructability of such structures using planar quadrilateral glass facets for the Jerusalem Museum of Tolerance project by Gehry Partners, in collaboration with Schlaich Bergermann & Partners, engineers. The challenge here lies not only in the development of a geometric strategy for generating quadrilateral planar facet solutions, but also in the fact that said solutions must closely match the designs created initially in physical model form by the architects. We describe a simple but robust geometric method for achieving the structure by incorporating the necessary geometric principles into a computational parametric framework using the CATIA Version 5 system. This generative system consists of a hierarchical set of geometric 'control elements' that drive the design toward constructible configurations. Optimization techniques for approximating the generated structural shape to the original created by the designers are also described. The paper presents the underlying geometric principles to the strategy and the resulting computational approach. (C) 2003 Published by Elsevier B.V.