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Related papers: Unfolding Smooth Prismatoids

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We address the unsolved problem of unfolding prismatoids in a new context, viewing a "topless prismatoid" as a convex patch---a polyhedral subset of the surface of a convex polyhedron homeomorphic to a disk. We show that several natural…

Computational Geometry · Computer Science 2012-05-10 Joseph O'Rourke

A $3$-Prismatoid is the convex hull of two convex polygons $A$ and $B$ which lie in parallel planes $H_A, H_B\subset\mathbb{R}^3$. Let $A'$ be the orthogonal projection of $A$ onto $H_B$. A prismatoid is called nested if $A'$ is properly…

Metric Geometry · Mathematics 2023-12-25 Manuel Radons

The notion of a spiral unfolding of a convex polyhedron, resulting by flattening a special type of Hamiltonian cut-path, is explored. The Platonic and Archimedian solids all have nonoverlapping spiral unfoldings, although among generic…

Computational Geometry · Computer Science 2015-10-20 Joseph O'Rourke

We show how to edge-unfold a new class of convex polyhedra, specifically a new class of prismatoids (the convex hull of two parallel convex polygons, called the top and base), by constructing a nonoverlapping "petal unfolding" in two new…

Computational Geometry · Computer Science 2021-06-29 Vincent Bian , Erik Demaine , Rachana Madhukara

This note shows that the hope expressed in [ADL+07]--that the new algorithm for edge-unfolding any polyhedral band without overlap might lead to an algorithm for unfolding any prismatoid without overlap--cannot be realized. A prismatoid is…

Computational Geometry · Computer Science 2007-10-04 Joseph O'Rourke

It remains unknown if every prismatoid has a nonoverlapping edge-unfolding, a special case of the long-unsolved "D\"urer's problem." Recently nested prismatoids have been settled [Rad24] by mixing (in some sense) the two natural unfoldings,…

Computational Geometry · Computer Science 2026-03-25 Joseph O'Rourke

An unfolding of a polyhedron along its edges is called a vertex unfolding if adjacent faces are allowed to be connected at not only an edge but also a vertex. Demaine et al showed that every triangulated polyhedron has a vertex unfolding.…

Combinatorics · Mathematics 2013-02-19 Toshiki Endo , Yuki Suzuki

An unfolding of a polyhedron is produced by cutting the surface and flattening to a single, connected, planar piece without overlap (except possibly at boundary points). It is a long unsolved problem to determine whether every polyhedron…

Computational Geometry · Computer Science 2007-05-23 Mirela Damian , Robin Flatland , Joseph O'Rourke

We define a new class of orthogonal polyhedra, called orthogrids, that can be unfolded without overlap with constant refinement of the gridded surface.

Computational Geometry · Computer Science 2013-10-18 Mirela Damian , Erik Demaine , Robin Flatland

We extend the notion of a source unfolding of a convex polyhedron P to be based on a closed polygonal curve Q in a particular class rather than based on a point. The class requires that Q "lives on a cone" to both sides; it includes simple,…

Computational Geometry · Computer Science 2012-05-07 Jin-ichi Itoh , Joseph O'Rourke , Costin Vilcu

It is shown that every orthogonal terrain, i.e., an orthogonal (right-angled) polyhedron based on a rectangle that meets every vertical line in a segment, has a grid unfolding: its surface may be unfolded to a single non-overlapping piece…

Computational Geometry · Computer Science 2007-07-12 Joseph O'Rourke

We present two algorithms for unfolding the surface of any polyhedron, all of whose faces are triangles, to a nonoverlapping, connected planar layout. The surface is cut only along polyhedron edges. The layout is connected, but it may have…

Computational Geometry · Computer Science 2010-01-21 Erik D. Demaine , David Eppstein , Jeff Erickson , George W. Hart , Joseph O'Rourke

This paper details an algorithm for unfolding a class of convex polyhedra, where each polyhedron in the class consists of a convex cap over a rectangular base, with several restrictions: the cap's faces are quadrilaterals, with vertices…

Computational Geometry · Computer Science 2007-09-12 Joseph O'Rourke

We study the continuous motion of smooth isometric embeddings of a planar surface in three-dimensional Euclidean space, and two related discrete analogues of these embeddings, polygonal embeddings and flat foldings without interior…

Computational Geometry · Computer Science 2023-09-29 David Eppstein

There exists a surface of a convex polyhedron P and a partition L of P into geodesic convex polygons such that there are no connected "edge" unfoldings of P without self-intersections (whose spanning tree is a subset of the edge skeleton of…

Computational Geometry · Computer Science 2008-10-06 Alexey S Tarasov

We extend the notion of a star unfolding to be based on a simple quasigeodesic loop Q rather than on a point. This gives a new general method to unfold the surface of any convex polyhedron P to a simple, planar polygon: shortest paths from…

Computational Geometry · Computer Science 2008-12-15 Jin-ichi Itoh , Joseph O'Rourke , Costin Vîlcu

We construct the first two continuous bloomings of all convex polyhedra. First, the source unfolding can be continuously bloomed. Second, any unfolding of a convex polyhedron can be refined (further cut, by a linear number of cuts) to have…

Computational Geometry · Computer Science 2009-06-16 Erik D. Demaine , Martin L. Demaine , Vi Hart , John Iacono , Stefan Langerman , Joseph O'Rourke

We extend the notion of star unfolding to be based on a quasigeodesic loop Q rather than on a point. This gives a new general method to unfold the surface of any convex polyhedron P to a simple (non-overlapping), planar polygon: cut along…

Computational Geometry · Computer Science 2009-06-24 Jin-ichi Itoh , Joseph O'Rourke , Costin Vîlcu

We present new examples of topologically convex edge-ununfoldable polyhedra, i.e., polyhedra that are combinatorially equivalent to convex polyhedra, yet cannot be cut along their edges and unfolded into one planar piece without overlap.…

Computational Geometry · Computer Science 2020-07-30 Erik D. Demaine , Martin L. Demaine , David Eppstein

An unzipping of a polyhedron P is a cut-path through its vertices that unfolds P to a non-overlapping shape in the plane. It is an open problem to decide if every convex P has an unzipping. Here we show that there are nearly flat convex…

Computational Geometry · Computer Science 2018-02-07 Joseph O'Rourke
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