Evolutionary Cooperative Design Methodology: The Genetic Sculpture Park

Abstract

The Genetic Sculpture Park seeks to engage artists and observers in a creative dialogue and to empower novices in the creation of complex computer-graphic models. Each visitor to the park experiences a unique set of sculptural forms and takes part in a cooperative conversation with the computer to produce more aesthetically pleasing designs. Inspired by Darwin's theory of evolution, the project uses genetic algorithms to allow visitors to "breed" forms tailored to their individual sense of aesthetics. In this article, the authors recount investigations into evolutionary design methodologies (using shampoo bottles and three-dimensional head models) and describe their implementation in the Genetic Sculpture Park, an interactive Java/Virtual Reality Modeling Language (VRML) world.

The productive engine of human creativity is one of the most celebrated of cognitive processes. The engineered form, shape and function of each newly created object is first born as a flash of insight in the imagination of an engineer. Given advances in our understanding of elements of creative cognition, it is clearly feasible to envision a specially tailored computer interface that can augment and support the cognitive processes of engineers. Such an interface could amplify the breadth, novelty and efficiency of key phases in the processes of visualization and decision that drive human creativity. Even a small improvement in the creativity of engineers can have dramatic impact on economic productivity. While many software tools, such as word-processing and CAD programs, support the crafting and manipulation of symbolic systems associated with creativity, few tools directly support the real engine of human creativity, the creative thinking process itself.

To be efficient and valuable, engineering creativity must satisfy special constraints. Engineering creativity is defined by how well an object, function or form serves the needs of a specific community of users. From the space of all possible objects or forms, the designer seeks a form that will work within (1) physical or functional constraints, (2) product semantic constraints (the form's perceived style and the meanings that form evokes in the user) and (3) aesthetic constraints. From the theoretical design space of all possible shapes, there are many acceptable and a few ideal solutions to the design problem within all three constraints.

Evolution of Form

In our previous studies [1], we allowed groups of subjects to selectively evolve shampoo bottle designs based on simple aesthetic criteria, such as "like"/"don't like" (our preliminary work had shown success with these broad definitions [2]). In this case, the subjects were simply asked to indicate either that they liked the design or that they did not. We specified shampoo bottles using an artificial genetic code that allowed shape and color to be evolved by selective combination. Each design was printed on a separate card and the stack of 90 cards was given to the subject to sort into one of two piles (the "I like this design" pile and the "I do not like this design" pile). This sorting was repeated

Fig. 1.

The upper pair of images shows different views of one specific subject's favorite head model from the initial population. The subject's preferences were used to drive the evolution of facial appearance; the lower pair of images shows this same subject's favorite head model after six generations. Subjects consistently preferred the more evolved faces. (© M.I.N.D. Lab)

Fig. 2.

A visit to the Genetic Sculpture Park. (© M.I.N.D. Lab)

for 40 subjects (newly selected for each generation), and a fitness was calculated for each design by counting how many times it was placed in the "I like this design" pile. Color Plate B No. 1 shows the visual effect of this selective evolution on the population. Further studies investigated the success of the evolution by comparing the highest-rated bottle from each population. Statistical analysis reveals that the more evolved a bottle was, the more highly it was rated.

We then extended the shampoo bottle studies, which were based on simple aesthetic preference, to evolve...