Description Changes in Architecture: Identity Rules in Shape Grammars and Multiplicity in Design Datasets

Abstract

This paper argues that changes or shifts in descriptions of architectural objects or elements have played a critical role in advancing architectural design across history. Description changes are possible when the elements are amenable to a multiplicity of interpretation, to shifts in their structural configuration, appearance, or stylistic meaning. An original compilation of examples is presented that illustrates such descriptive changes across history. These range from the formation of the Doric order to Romanesque, Gothic, Modern and Postmodern architecture. These descriptive changes are shown to have stimulated important generative processes, from forming the triglyph to crafting a Gothic pinnacle or spatially and structurally organizing Terragni's Danteum. The diversity of the examples demonstrates the relevance of descriptive change to all aspects of architecture: from purely structural to purely ornamental. "Description changes" are represented as rule-based computational processes guided by identity rules, a class of shape rules developed within the design computing theory area of shape grammars. The compilation of the examples illustrates how visual calculating with identity rules can be applied to real architectural contexts. Due to the rising interest in data-driven machine learning, whether for classification or for generative modeling, current architectural design discourse often revolves around a need for creating digital datasets that statically represent a record of architectural knowledge (e.g., plans, three-dimensional geometries, building component libraries). By raising the importance of description changes that have characterized architectural innovation, this paper argues for adopting a new lens in the representation of architectural knowledge in data, namely, one that embraces the possibility and need for changes in descriptions of architectural elements and a multiplicity in their meanings.