Interactive visualization for parametric design space exploration

Designers engage, iteratively, in rapid creation, evaluation, and modification of multiple designs during the design process and this activity resembles a `dialog' with the design medium. The outcome of this process results in the generation of multiple alternative designs. Parametric modeling tools in Architecture, popularly known as pCAD, partially support exploration of design alternatives by the varying of parameters that control the design state. However, the support for 'dialog' like creation and evaluation of multiple alternatives is poor. Proposals in the literature to support design alternatives either focus on information comparison, where the abilities to compare information regarding design alternatives are strong, but lack support for iterative creation or modification. Vice-versa, some proposals support creation and modification of alternatives simultaneously, but do not have strong information comparison abilities. In both cases, the proposals do not explicitly cater to parametric modeling, and rarely any support working with actual parametric modeling tools as encountered in architectural practice. The lack of interfaces with the comprehensive capabilities of rapid generation, comparison, and modification of a large number of design alternatives created from popular parametric modeling tools used in architectural practice is the research problem. Using the research through design methodology, through iteration and evaluation cycles, I present an interface that uses the gallery metaphor to visualize design alternatives in many different forms (views). A novel parallel coordinate-based interactive visualization interface is integrated with the gallery that enables the rapid creation, evaluation, and modification of design alternatives simultaneously as required in the research problem. All interaction with alternatives are coordinated across different view types. The interface can be easily integrated with popular parametric modeling tools used in architectural practice. Put together, this interface contains novel and significant inventions in interaction and interface design to support working with design alternatives. The goal was to obtain a critique of the interface, at each stage of iteration, if used in practice; how it would affect designers' exploration patterns and if any novel patterns emerged; and whether there were any usability benefits. The evaluation techniques involved participant observation, and controlled experiments with expert users performing open-ended tasks followed by interviews. Among many, findings indicate that all iterations of the interface provide significant usability benefits in interacting with alternatives compared to existing tools and methods. Specifically, each iteration enabled a continuous dialog like interaction when it came to creating, comparing, and modifying alternatives, and it was noted that designers preferred the novel interfaces to generate alternatives rather than the modeling tools. The information comparison and alternative generation capabilities were regarded to be the most beneficial by users. There is also indication that the interface encouraged expert designer behaviour by enabling breadth-first exploration of alternatives. Overall, the output of research through design opens up a design space for novel, mixed-initiative ways of visually exploring parameter spaces and working with design alternatives.