Shape Programming & Self-Assembly of Bead Structures

conducted for the M.S. in Matter Design Computation at Cornell University College of Art, Architecture, and Planning

This project demonstrates the potential of a robust, low-cost approach to programmable matter using beads and string to achieve complex shapes with novel self-organizing and deformational properties. The method is inspired by the observation that beads forced together along a string will become constrained until they form a uniform rigid shape. This behavior is easily observed in any household string and flat-faced beads and recalls the mechanism behind classic crafts such as push puppets. However, specific examples of architectural applications are lacking. We analyze how this phenomenon occurs through static force analyses, physical tests, and simulation, using a rigid body physics engine to validate digital prototypes. We develop a method of designing custom bead geometries able to be produced via generic 3d printing technology, as well as a computational path-planning toolkit for designing ways of threading beads together. We demonstrate how these custom bead geometries and threading paths influence the acquired structure and its assembly. Finally, we explore a means of scaling up this phenomenon by fabricating in carveable foam, suggesting potential applications in deployable architecture, mortarless assembly of non-funicular masonry, and responsive architectural systems. See the full paper.

15” counterweighted 2-cord model. A beadwork assembly can order itself into a self-standing structure with little to no aid.

Still from rigid-body simulation.

Maximum angle attainable between cylindrical beads as a function of the length of cord separating them. Note that θmax → 0 as l → 0, continuously but with discontinuous first derivative at l = 2r and l = r. This graph illustrates the shrinking of the configuration space with the tensioning of the system.

Configuration space of conical interlocking beads, shown in section. The 3d graph of the configuration space boundary is discontinuous for τ < π/2.

Tubular beads: The angle θ of three-point contact can be determined for a given outer radius R, wall thickness t, and axial offset o of one bead with respect to the next.

4-bead segment sculpted by ABB robot-mounted nichrome wire cutter showing rigidifying properties, without mortar or other adhesive