Bend-It: Design and Fabrication of Kinetic Wire Characters

摘要

Elastically deforming wire structures are lightweight, durable, and can bebent within minutes using CNC bending machines. We present a computationaltechnique for the design of kinetic wire characters, tailored for fabricationon consumer-grade hardware. Our technique takes as input a network ofcurves or a skeletal animation, then estimates a cable-driven, compliant wirestructure which matches user-selected targets or keyframes as closely as possible.To enable large localized deformations, we shape wire into functionalspring-like entities at a discrete set of locations.We first detect regions wherechanges to local stiffness properties are needed, then insert bendable entitiesof varying shape and size. To avoid a discrete optimization, we first optimizestiffness properties of generic, non-fabricable entities which capture wellthe behavior of our bendable designs. To co-optimize stiffness propertiesand cable forces, we formulate an equilibrium-constrained minimizationproblem, safeguarding against inelastic deformations. We demonstrate ourmethod on six fabricated examples, showcasing rich behavior includinglarge deformations and complex, spatial motion.