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Content Provider | ACM Digital Library |
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Author | Chazelle, B. Guibas, L. Sharir, M. Edelsbrunner, H. |
Abstract | We study combinatorial and algorithmic problems involving arrangements of n lines in 3-dimensional space, and then present applications of our results to a variety of problems on polyhedral terrains. Our main results include:A tight &THgr;(n2) bound on the complexity of the space of all lines passing above all the n given lines (their “upper envelope”) and satisfying a certain orientation consistency constraint.A preprocessing procedure using near-quadratic time and storage that builds a structure supporting &Ogr;(log n) time queries for testing if a line lies above all the given lines.An &Ogr;(n4/3+ε) randomized expected time algorithm, for any fixed ε > 0, that tests the “towering property”: do n given red lines lie all above n given blue lines?A preprocessing procedure for a polyhedral terrain &Sgr; with n edges, that uses near-quadratic time and storage and builds a structure supporting &Ogr;(log2 n) time rayshooting queries for computing the first intersection of an arbitrary query ray with &Sgr;.Finding the smallest vertical distance between two disjoint polyhedral terrains with a total of n edges, in time &Ogr;(n4/3+ε), for any ε > 0.Computing the upper envelope (pointwise maximum) of two polyhedral terrains with a total of n edges, in time &Ogr;(n1.5+ε + klog2 n), for any ε > 0, where &kgr; is the size of the output envelope.The tools used to obtain these results include Plücker coordinates for lines in space, random sampling in geometric problems, and a new variant of segment trees. |
Starting Page | 382 |
Ending Page | 393 |
Page Count | 12 |
File Format | |
ISBN | 0897913078 |
DOI | 10.1145/73007.73044 |
Language | English |
Publisher | Association for Computing Machinery (ACM) |
Publisher Date | 1989-02-01 |
Publisher Place | New York |
Access Restriction | Subscribed |
Content Type | Text |
Resource Type | Article |
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