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Related papers: Locked and Unlocked Polygonal Chains in 3D

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In this paper, we study movements of simple polygonal chains in 3D. We say that an open, simple polygonal chain can be straightened if it can be continuously reconfigured to a straight sequence of segments in such a manner that both the…

Computational Geometry · Computer Science 2007-05-23 T. Biedl , E. Demaine , M. Demaine , S. Lazard , A. Lubiw , J. O'Rourke , M. Overmars , S. Robbins , I. Streinu , G. Toussaint , S. Whitesides

We prove that, in all dimensions d>=4, every simple open polygonal chain and every tree may be straightened, and every simple closed polygonal chain may be convexified. These reconfigurations can be achieved by algorithms that use…

Computational Geometry · Computer Science 2007-05-23 Roxana Cocan , Joseph O'Rourke

It has recently been shown that any simple (i.e. nonintersecting) polygonal chain in the plane can be reconfigured to lie on a straight line, and any simple polygon can be reconfigured to be convex. This result cannot be extended to tree…

We extend linkage unfolding results from the well-studied case of polygonal linkages to the more general case of linkages of polygons. More precisely, we consider chains of nonoverlapping rigid planar shapes (Jordan regions) that are hinged…

A kinematic chain in three-dimensional Euclidean space consists of $n$ links that are connected by spherical joints. Such a chain is said to be within a closed configuration when its link lengths form a closed polygonal chain in three…

Robotics · Computer Science 2021-08-02 Gerhard Zangerl , Alexander Steinicke

A planar kinematic chain consists of $n$ links connected by joints. In this work we investigate the space of configurations, described in terms of joint angles, that guarantee that the kinematic chain is closed. We give explicit formulas…

Metric Geometry · Mathematics 2021-12-03 Gerhard Zangerl

Planar/flat configurations of fixed-angle chains and trees are well studied in the context of polymer science, molecular biology, and puzzles. In this paper, we focus on a simple type of fixed-angle linkage: every edge has unit length…

Computational Geometry · Computer Science 2022-12-26 Erik D. Demaine , Hiro Ito , Jayson Lynch , Ryuhei Uehara

The resolution of a decades-old open problem is described: polygonal chains cannot lock in the plane.

Computational Geometry · Computer Science 2007-05-23 Joseph O'Rourke

A loop of chain can move along its own tangents, maintaining a steady shape. An open-ended chain undergoing a nontrivial motion must change its shape. One consequence is that chains pulled around objects will fail to follow the contours of…

Fluid Dynamics · Physics 2012-09-05 A. D. Cambou , B. D. Gamari , E. Hamm , J. A. Hanna , N. Menon , C. D. Santangelo , L. Walsh

We prove that any finite collection of polygons of equal area has a common hinged dissection. That is, for any such collection of polygons there exists a chain of polygons hinged at vertices that can be folded in the plane continuously…

Computational Geometry · Computer Science 2008-06-12 Timothy G. Abbott , Zachary Abel , David Charlton , Erik D. Demaine , Martin L. Demaine , Scott D. Kominers

Deciding whether a family of disjoint line segments in the plane can be linked into a simple polygon (or a simple polygonal chain) by adding segments between their endpoints is NP-hard.

Computational Geometry · Computer Science 2021-09-03 Rain Jiang , Kai Jiang , Minghui Jiang

A flipturn is an operation that transforms a nonconvex simple polygon into another simple polygon, by rotating a concavity 180 degrees around the midpoint of its bounding convex hull edge. Joss and Shannon proved in 1973 that a sequence of…

Deciding whether a family of disjoint axis-parallel line segments in the plane can be linked into a simple polygon (or a simple polygonal chain) by adding segments between their endpoints is NP-hard.

Computational Geometry · Computer Science 2021-09-07 Rain Jiang , Kai Jiang , Minghui Jiang

Soss proved that it is NP-hard to find the maximum 2D span of a fixed-angle polygonal chain: the largest distance achievable between the endpoints in a planar embedding. These fixed-angle chains can serve as models of protein backbones. The…

Computational Geometry · Computer Science 2010-06-03 Nadia Benbernou , Joseph O'Rourke

Herein, we describe new methods to produce colloidal particle chains of three stiffness regimes that can be observed on a single-particle level, that is, on the level of the monomers that make up the chain; the chains can even be observed…

We present design and implementation of a chain of particles that can be programmed to fold the chain into a given curve. The particles guide an external force to fold, therefore the particles are simple and amenable for miniaturization. A…

Robotics · Computer Science 2014-02-12 Matteo Lasagni , Kay Römer

The visibility graph of a simple polygon represents visibility relations between its vertices. Knowing the correct order of the vertices around the boundary of a polygon and its visibility graph, it is an open problem to locate the vertices…

Computational Geometry · Computer Science 2019-05-03 Sahar Mehrpour , Alireza Zarei

We study oriented connected closed polyhedral surfaces with non-degenerate triangular faces in three-dimensional Euclidean space, calling them polyhedra for short. A polyhedron is called flexible if its spatial shape can be changed…

Metric Geometry · Mathematics 2020-06-08 Victor Alexandrov

Closed kinematic chains are created whenever multiple robot arms concurrently manipulate a single object. The closed-chain constraint, when coupled with robot joint limits, dramatically changes the connectivity of the configuration space.…

Robotics · Computer Science 2017-06-22 Xian Zhou , Puttichai Lertkultanon , Quang-Cuong Pham

We explore the following problem: given a collection of creases on a piece of paper, each assigned a folding direction of mountain or valley, is there a flat folding by a sequence of simple folds? There are several models of simple folds;…

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