Morphogenetic Design Experiment 02

The main aim of this morphogenetic experiment, a design commission for a pneumatic strawberry bar for the Architectural Association’s annual project review, was extending the evolutionary dynamics of reproduction, mutation, competition and selection as design strategies. The potentials and limits from initial form-generation to the actual manufacturing process were explored by shifting the investigation towards performative patterns that evolve as species across populations and successive generations whilst maintaining structural capacity and geometric characteristics.

The logic of a pneumatic component is defined by the geometry of its cutting pattern, and this was the starting point for the development process. The pneumatic component of the experiment consisted of two trapeziform surfaces that are aligned at a datum, the plane of the connecting seams. The inflated component is a three dimensional form defined by the different length of the surfaces in relation to the defining points and the spatial datum. These simple geometric relations, defined as a generic 3D cutting-pattern, provided the base data for the subsequent process that simultaneously grew three sub-populations of surfaces. Two subpopulations evolved the definition points of the shorter and the longer surface, and one that defined the spatial datum. According to the logic of the pneumatic base component specific fitness criteria for each sub-population of the geometry-defining surfaces were established, which influenced the global undulation and surface subdivision in relation to parametric variables such as the scale factor of growth, branch length and branch angles.

The evolving points of local maximum distances between the shorter and the longer surface in relation to the datum surface established the definition points of the pneumatic system. Rather than breeding just one surface, this method instigated a feedback loop by continuously using the bounding box of the most recently evolved surface as the environment in which the next surface would be grown. This method maintained the inherent logic of the pneumatic component in a larger system but dissolved the distinction between environmental constraints and individual response. Another feedback loop utilised digital form-finding in a dedicated membrane engineering software, and additional physical test-modelling further informed the evolutionary process and its evaluation.

After running the evolutionary process over 600 generations 144 species were identified and catalogued according to specific patterns of relevant geometric features. Considering the interrelated evolution of the geometry-defining surfaces the criteria for evaluation was the relative fitness amongst the emergent species rather than the absolute fitness ranking of any particular individuals. As the structural behaviour of the pneumatic system primarily relied on specific geometric relations such as alignment and proportional distances of definition points, the species of individuals that shared these geometric features was selected. Then the individual of the chosen species that grew in the last and most developed generation was picked. The genotype of this individual incorporated the genomes of three geometry-defining surfaces, establishing a degree of phenotypic plasticity that allowed the resulting pneumatic system to adjust to the constraints of a digital cutting pattern and computer-aided manufacturing process.

Morphogenetic Design Experiment 02 – AA Strawberry Bar
Achim Menges, Martin Hemberg (Software Development)