The shape grammar is the formalism employed to encode the Thonet chair design style. The goal is twofold: 1) to explain the style as a design language; and 2) to enable new designs to be generated according to the established principles of the language.
The Thonet design style comprises a set of design principles that is embedded in the selected corpus constituted by six chairs. It is based on a modular strategy that relies on the interchangeability of components and focuses mainly on different designs for the back insert.
The goal of the shape grammar is to translate the shape and material-related aspects into a set of rules that enable multiple design solutions to be generated, in addition to the corpus. This premise provides the means to define the design process for mass customisation in a way that extends beyond the discrete solutions permitted by the modular strategy, thus constituting a new strategy for the furniture design industry.
The shape grammar formalism is first used to capture the rules of formal composition for the Thonet design style and then to generate new designs through the creative application of these rules. The shape grammar becomes the guiding information for the generative design system, enabling a design language defined by a designer to be customised. In order to meet the requirement of assisting the designer in the exploration of custom solutions, while implementing a mass customisation process, the shape grammar must be encoded in CAD software.