[Qhull-cvsupdate] qvoronoi options

[Brad Barber]

>
>Message: 1
>Date: Thu, 11 Sep 2003 13:37:25 -0400
>From: Frederic Leymarie <address@hidden>
>Subject: [Qhull-cvsupdate] options with qvoronoi
>
>Hi there
>
>
>I downloaded the latest (I believe) version of the qhull package
>from http://savannah.nongnu.org/projects/qhull/

        2003.1 from www.qhull.org


>I can install everything nicely; great!
>
>Now, using qvoronoi I cannot find options to do the following:
>
>    1- For each voronoi vertex how can I get (directly)
>        the list of associated input sites ?
>        (I am working with 3D data, so that would be 4 generators per vertex).

'i' lists the corresponding Delaunay triangles (i.e., the generators)


>    2- With option Fv, I get connectivity amongst vertices bounding
>        a hyperplane, the bisector of a pair of sites. This is what you
>        call ridge.  In 3D, each connector between pairs of these bounding
>        Voronoi vertices defines a line segment also bounding the
>        the bisector. I have two related questions:
>            a- is the series of Voronoi vertices defining the ridge of
>                a specific bisector ordered ? i.e., does it represent
>                systematically a sequential walk-through the looping structure
>                of the boundary of the bisector.

No.   Recovering the full topological structure of the Voronoi diagram is 
difficult.  There is no direct access to this information.  You can run qconvex 
on the vertices of one region to recover the topological information for the 
region.  Let me know if you come up with a better solution.   It would need to 
work with non-simplicial Delaunay triangulations (i.e., input data with 
cospherical sites).  It may be easier to triangulate the Delaunay triangulation 
using 'Qt', and then merging the duplicated vertices.

>            b- similarly to question 1 above, how can i get (directly)
>                the input sites associated to each bounding curve segment
>                forming the ridge, e.g., the 3 input sites shared by each
>                pair of connected Voronoi vertices along the ridge?

I believe this is the ridges of the corresponding Delaunay triangulation.

                                        --Brad
                                 



>Thanking you for any help in these matters,
>Frederic
>
>
>
>
>--
>Frederic FOL LEYMARIE, Ph.D., Manager of the SHAPE Lab.
>http://www.lems.brown.edu/shape/
>Brown University, Division of Engineering, LEMS, Box D
>182-4 Hope Street, Providence, Rhode Island 02912, U.S.A.
>Tel: +1.401.863.2760, Alternate Voice: x2177, Fax: x9039
>mailto:address@hidden , http://www.lems.brown.edu/~leymarie
>---
>It does play with dice ... but are they fixed?
>
>
>
>
>
>
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>End of Qhull-cvsupdate Digest, Vol 1, Issue 12
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