Quantification of Symmetry, Parallelism, and Continuity as Continuous Design Variables for Three-Dimensional Product Representations

This work introduces a methodology to quantify the form of a three-dimensional (3D) product representation using the Gestalt principles of symmetry, parallelism, and continuity, and how they can be used as descriptive parameters in product design. First, consistent quantifications of these three Gestalt principles for parametrized 3D representations in a zero-one scale are presented. Then, a generalized methodology applicable to any product form is discussed. It starts with the identification of important aesthetic forms of the product shape and the Gestalt principles that best related to those forms, and ends with the quantification of these Gestalt principles of a 3D product representation. The expressions to quantify the Gestalt principles in question are validated through an online survey in which subjects indicated how much they recognize symmetry, parallelism, or continuity from irregular shapes. Finally, random-effects ordered logit regression is used to determine if the expressions effectively describe the level of recognition of each Gestalt principle. Results show that the proposed quantifications for symmetry, parallelism, and continuity are congruent with subjects perception of these Gestalt principles, and the implications for designers and future work are discussed. Further implications in the design process of these quantifications include the optimization of the product shape for aesthetic, semantic, and functional goals.