POV-Ray : Newsgroups : povray.general : looking for a macro to turn an array of points into one of triangles.... Server Time
4 Nov 2024 17:29:00 EST (-0500)
  looking for a macro to turn an array of points into one of triangles.... (Message 1 to 4 of 4)  
From: Habagat Boy
Subject: looking for a macro to turn an array of points into one of triangles....
Date: 6 Dec 2003 13:20:02
Message: <web.3fd21c9aca6ea6d53527d1b40@news.povray.org>
does anyone know of a way to convert an array of points into non-overlapping

series of points, and test the first array for distance to each point; the
three closest points on the first array to a point on the second set become
the vertices of a triangle. however, this will result in a lot of identical


Post a reply to this message

From: Christopher James Huff
Subject: Re: looking for a macro to turn an array of points into one of triangles....
Date: 6 Dec 2003 14:30:58
Message: <cjameshuff-78A169.14303706122003@netplex.aussie.org>
In article <web.3fd21c9aca6ea6d53527d1b40@news.povray.org>,
 "Habagat Boy" <hab### [at] yahoocom> wrote:

> does anyone know of a way to convert an array of points into non-overlapping

> series of points, and test the first array for distance to each point; the
> three closest points on the first array to a point on the second set become
> the vertices of a triangle. however, this will result in a lot of identical


Creating a triangle mesh from an unordered set of points is a very 
difficult problem. There are ways to do it, but it is still an area of 
active research...and simple points do not have enough information to 
unambiguously reconstruct the original surface. Doing this in POV script 
is probably impractical.

If you have a bit more information about the points, it makes the 
problem a lot easier. For instance, if you know they are points of a 
height field, it is pretty simple to generate a height field mesh.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/


Post a reply to this message

From: JC (Exether)
Subject: Re: looking for a macro to turn an array of points into one of triangles....
Date: 6 Dec 2003 14:45:51
Message: <3fd231ef$1@news.povray.org>
The Delaunay triangulation provides a more optimized algorithm for doing 
the distance comparison and building the triangles. But as Christopher 
pointed, this operation will result in the wanted mesh only if you have 
a set of points with certain properties.

I have writen and posted a POV-script delaunay algorithm, but it's a 2D 
algo while you need a 3D one. You should be able to find it in 

useful in your case, it can point you toward interesting links on the net.

I hope that helps,

JC

Habagat Boy wrote:
> does anyone know of a way to convert an array of points into non-overlapping

> series of points, and test the first array for distance to each point; the
> three closest points on the first array to a point on the second set become
> the vertices of a triangle. however, this will result in a lot of identical

>


Post a reply to this message

From: Habagat Boy
Subject: Re: looking for a macro to turn an array of points into one of triangles...=
Date: 10 Dec 2003 14:15:01
Message: <web.3fd770a3fa5134f7403272380@news.povray.org>
JC (Exether) wrote:
>The Delaunay triangulation provides a more optimized algorithm for doing
>the distance comparison and building the triangles. But as Christopher
>pointed, this operation will result in the wanted mesh only if you have
>a set of points with certain properties.
>
>I have writen and posted a POV-script delaunay algorithm, but it's a 2D
>algo while you need a 3D one. You should be able to find it in

>useful in your case, it can point you toward interesting links on the net.
>
>I hope that helps,


them a 0 z-value, since I plan to start off with a flat surface first, then
do transformations from there to get the exact shape I want.... Thanks! =)


Post a reply to this message

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.