Packable Springs

publication
EUROGRAPHICS 2018
authors
Katja Wolff, Roi Poranne, Oliver Glauser, Olga Sorkine-Hornung

Packable Springs

Given an input object (a), we construct a spring representation (b), such that the springs consist of a small number of packable parts, which can be flattened to a plane. This allows us to laser cut the springs from a small number of flat material sheets (c) and easily assemble them to form their intended shape in 3D (d). This structure can serve as formwork for a multitude of different materials and applications, e.g. for sculpting with clay (e).

abstract

Laser cutting is an appealing fabrication process due to the low cost of materials and extremely fast fabrication. However, the design space afforded by laser cutting is limited, since only flat panels can be cut. Previous methods for manufacturing from flat sheets usually roughly approximate 3D objects by polyhedrons or cross sections. Computational design methods for connecting, interlocking, or folding several laser cut panels have been introduced; to obtain a good approximation, these methods require numerous parts and long assembly times. In this paper, we propose a radically different approach: Our approximation is based on cutting thin, planar spirals out of flat panels. When such spirals are pulled apart, they take on the shape of a 3D spring whose contours are similar to the input object. We devise an optimization problem that aims to minimize the number of required parts, thus reducing costs and fabrication time, while at the same time ensuring that the resulting spring mimics the shape of the original object. In addition to rapid fabrication and assembly, our method enables compact packaging and storage as flat parts. We also demonstrate its use for creating armatures for sculptures and moulds for filling, with potential applications in architecture or construction.

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acknowledgments

This work was supported in part by the NCCR Digital Fabrication, funded by the Swiss National Science Foundation Agreement #51NF40-141853, and by the European Research Council under Grant No. StG-2012-306877 (iModel). We thank Christian Schüller for providing us with his code for adaptive remeshing.