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We present the Shape Part Slot Machine, a new method for assembling novel 3D shapes from existing parts by performing contact-based reasoning. Our method represents each shape as a graph of ``slots,'' where each slot is a region of contact…

Graphics · Computer Science 2022-07-25 Kai Wang , Paul Guerrero , Vladimir Kim , Siddhartha Chaudhuri , Minhyuk Sung , Daniel Ritchie

This paper presents Polylidar, an efficient algorithm to extract non-convex polygons from 2D point sets, including interior holes. Plane segmented point clouds can be input into Polylidar to extract their polygonal counterpart, thereby…

Computational Geometry · Computer Science 2020-07-24 Jeremy Castagno , Ella Atkins

We give a $O(n)$-time algorithm for determining whether translations of a polyomino with $n$ edges can tile the plane. The algorithm is also a $O(n)$-time algorithm for enumerating all such tilings that are also regular, and we prove that…

Computational Geometry · Computer Science 2015-09-23 Andrew Winslow

This paper presents a point cloud based robotic system for arc welding. Using hand gesture controls, the system scans partial point cloud views of workpiece and reconstructs them into a complete 3D model by a linear iterative closest point…

Robotics · Computer Science 2020-11-25 Peng Zhou , Rui Peng , Maggie Xu , Victor Wu , David Navarro-Alarcon

A polyomino is a polygonal region with axis parallel edges and corners of integral coordinates, which may have holes. In this paper, we consider planar tiling and packing problems with polyomino pieces and a polyomino container $P$. We give…

Computational Geometry · Computer Science 2021-08-10 Anders Aamand , Mikkel Abrahamsen , Thomas D. Ahle , Peter M. R. Rasmussen

A new algorithm for computing a point on a polynomial or rational curve in B\'{e}zier form is proposed. The method has a geometric interpretation and uses only convex combinations of control points. The new algorithm's computational…

Numerical Analysis · Computer Science 2019-06-20 Filip Chudy , Paweł Woźny

Let $P$ and $Q$ be two simple polygons in the plane of total complexity $n$, each of which can be decomposed into at most $k$ convex parts. We present an $(1-\varepsilon)$-approximation algorithm, for finding the translation of $Q$, which…

Computational Geometry · Computer Science 2014-06-24 Sariel Har-Peled , Subhro Roy

We consider the task of reconstructing polytopes with fixed facet directions from finitely many support function evaluations. We show that for a fixed simplicial normal fan the least-squares estimate is given by a convex quadratic program.…

Metric Geometry · Mathematics 2023-02-03 Maria Dostert , Katharina Jochemko

Cutting planes are a key ingredient to successfully solve mixed-integer linear programs. For specific problems, their strength is often theoretically assessed by showing that they are facet-defining for the corresponding mixed-integer hull.…

Discrete Mathematics · Computer Science 2020-11-13 Matthias Walter

Based on the characterization of the polyconvex envelope of isotropic functions by their signed singular value representations, we propose a simple algorithm for the numerical approximation of the polyconvex envelope. Instead of operating…

Numerical Analysis · Mathematics 2023-07-31 Timo Neumeier , Malte A. Peter , Daniel Peterseim , David Wiedemann

We study the problem of computing a convex region with bounded area and diameter that contains the maximum number of points from a given point set $P$. We show that this problem can be solved in $O(n^6k)$ time and $O(n^3k)$ space, where $n$…

Computational Geometry · Computer Science 2025-07-08 Gianmarco Picarella , Marc van Kreveld , Frank Staals , Sjoerd de Vries

A convex polygon Q is circumscribed about a convex polygon P if every vertex of P lies on at least one side of Q. We present an algorithm for finding a maximum area convex polygon circumscribed about any given convex n-gon in O(n^3) time.…

Metric Geometry · Mathematics 2024-03-25 Markus Ausserhofer , Susanna Dann , Zsolt Lángi , Géza Tóth

Given an undirected, unweighted graph with $n$ vertices and $m$ edges, the maximum cut problem is to find a partition of the $n$ vertices into disjoint subsets $V_1$ and $V_2$ such that the number of edges between them is as large as…

We consider worst case time bounds for NP-complete problems including 3-SAT, 3-coloring, 3-edge-coloring, and 3-list-coloring. Our algorithms are based on a constraint satisfaction (CSP) formulation of these problems. 3-SAT is equivalent to…

Data Structures and Algorithms · Computer Science 2010-01-21 Richard Beigel , David Eppstein

A constant-workspace algorithm has read-only access to an input array and may use only O(1) additional words of $O(\log n)$ bits, where $n$ is the size of the input. We assume that a simple $n$-gon is given by the ordered sequence of its…

Computational Geometry · Computer Science 2013-06-14 Tetsuo Asano , Kevin Buchin , Maike Buchin , Matias Korman , Wolfgang Mulzer , Günter Rote , André Schulz

In this note we prove a theorem concerning the sewing of even dimensional neighbourly polytopes. The theorem provides a fast algorithm for sewing in practice. We also give a description of the universal faces of a sewn $d$-polytope in terms…

Metric Geometry · Mathematics 2011-02-25 Ryan Trelford , Viktor Vigh

This paper presents a fully automatic framework for extracting editable 3D objects directly from a single photograph. Unlike previous methods which recover either depth maps, point clouds, or mesh surfaces, we aim to recover 3D objects with…

Computer Vision and Pattern Recognition · Computer Science 2020-05-29 Xin Chen , Yuwei Li , Xi Luo , Tianjia Shao , Jingyi Yu , Kun Zhou , Youyi Zheng

We study the problem of ordered stabbing of $n$ balls (of arbitrary and possibly different radii, no ball contained in another) in $\mathbb{R}^d$, $d \geq 3$, with either a directed line segment or a (directed) polygonal curve. Here, the…

Computational Geometry · Computer Science 2023-02-13 Alexander Neuhaus , Dennis Rohde

Let $G$ be a planar $3$-graph (i.e., a planar graph with vertex degree at most three) with $n$ vertices. We present the first $O(n^2)$-time algorithm that computes a planar orthogonal drawing of $G$ with the minimum number of bends in the…

Data Structures and Algorithms · Computer Science 2018-09-06 Walter Didimo , Giuseppe Liotta , Maurizio Patrignani

Given a graph $G$ and two vertices $s$ and $t$ in it, {\em graph reachability} is the problem of checking whether there exists a path from $s$ to $t$ in $G$. We show that reachability in directed layered planar graphs can be decided in…

Data Structures and Algorithms · Computer Science 2015-01-26 Diptarka Chakraborty , Raghunath Tewari