Enlisting Clustering and Graph-Traversal Methods for Cutting Pattern and Net Topology Design in Pneumatic Hybrids

Cutting patterns for architectural membranes are generally characterised by rational approaches to surface discretisation and minimisation of geometric deviation between discrete elements that comprise the membrane. In this paper, we present an alternative approach for cutting pattern generation to those described in the literature. Our method employs computational techniques of clustering and graph-traversal to operate on arbitrary design meshes. These design meshes can contain complex curvature, including anticlastic curvatures. Curvature analysis of the design mesh provides the input to the cutting pattern generation method and the net topology generation method used to produce a constraint net for a given membrane. We test our computational design approach through an iterative cycle of digital and physical prototyping before realising an air-inflated cable restrained pneumatic structural hybrid, at full-scale. Using a Lidar captured point-cloud model, we evaluate our results by comparing the geometrical deviation of the realised structure to that of the target design geometry. We argue that this work presents new potentials for membrane expression and aesthetic by allowing free-patterning of the membrane, but identify current limits of the workflow that impede the use of the design method across the breadth of current architectural membrane applications. Nevertheless, we identify possible architectural scenarios in which the current method would be suitable.