How are users creating multiple triangles from data sets

Can't seem to find utilities for this.

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In article <38ad94ec@news.povray.org>, "David Vincent-Jones" 
<geo### [at] galaxynetcom> wrote:

> How are users creating multiple triangles from data sets
> 
> Can't seem to find utilities for this.

Can you provide more information about what exactly you want? And for 
which platform?

Are you looking for a conversion utility which converts from some other 
mesh format to POV-Ray format? Or something that will take data and 
output triangles? If the latter, what format is the data in?

-- 
Chris Huff
e-mail: chr### [at] yahoocom
Web page: http://chrishuff.dhs.org/

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I would like to put in a list of 3D points and finish up with a set of
triangles that I can massage into a mesh_triangle set.

I would like to try this as an alternate to gridding the data and then
displaying as a height_field.

I am using MS Windows and see several progs for Unix based systems but not
MS.W.

David

Chris Huff <chr### [at] yahoocom> wrote in message
news:chrishuff_99-58E055.14124618022000@news.povray.org...
> In article <38ad94ec@news.povray.org>, "David Vincent-Jones"
> <geo### [at] galaxynetcom> wrote:
>
> > How are users creating multiple triangles from data sets
> >
> > Can't seem to find utilities for this.
>
> Can you provide more information about what exactly you want? And for
> which platform?
>
> Are you looking for a conversion utility which converts from some other
> mesh format to POV-Ray format? Or something that will take data and
> output triangles? If the latter, what format is the data in?
>
> --
> Chris Huff
> e-mail: chr### [at] yahoocom
> Web page: http://chrishuff.dhs.org/

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David Vincent-Jones wrote:
> 
> I would like to put in a list of 3D points and finish up with a set of
> triangles that I can massage into a mesh_triangle set.

It sounds like you are describing what is known as a point cloud. Each
reference point of data is given as a single 3D coordinate rather than
a list of vertices that most 3D formats use. I too have looked for
software that will accomplish what you are looking for and have found
a definate lack of software to do this on any platform. I am sure it is
possible to write software to do this but you would have to have a strict
set of rules for the point cloud so that the software can logically connect
the individual points for you. Otherwise you will get a meaningless
jumble of triangles.

Good Luck,

-- 
Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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Ken wrote:

>David Vincent-Jones wrote:
>> 
>> I would like to put in a list of 3D points and finish up with a set of
>> triangles that I can massage into a mesh_triangle set.
>
>It sounds like you are describing what is known as a point cloud. 
>......
> Otherwise you will get a meaningless jumble of triangles.

No triangle solution, but thinking loud;
-How about using a blob with a component at each coordinate?
-Could a pointcloud be turned into a datafile that can be used to make an 
isosurface object (i_dat3d library) in MegaPov?

Ingo

-- 
Photography: http://members.home.nl/ingoogni/
Pov-Ray    : http://members.home.nl/seed7/

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On Fri, 18 Feb 2000 13:03:33 -0800, "David Vincent-Jones"
<geo### [at] galaxynetcom> wrote:

>I would like to put in a list of 3D points and finish up with a set of
>triangles that I can massage into a mesh_triangle set.
>
>I would like to try this as an alternate to gridding the data and then
>displaying as a height_field.
>
>I am using MS Windows and see several progs for Unix based systems but not
>MS.W.

Can you please send me the links to these Unix programs (or the
programs if you can fit everything in under 500k)? I'll check and see
if any of them does what you want, then maybe recompile it for Win32
if I can.


Peter Popov
pet### [at] usanet
ICQ: 15002700

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Peter;

Here are 2 that may be worth looking at.

I used a search on 'Delaunay and Triangular ' to find them.

The second item has quite a good description of the process

ftp://ftp.ncsa.uiuc.edu/SGI/MinMaxer
http://www.cs.cmu.edu/~quake/triangle.html

David

Peter Popov <pet### [at] usanet> wrote in message news:icetOGE8Jlj6Q1...
> On Fri, 18 Feb 2000 13:03:33 -0800, "David Vincent-Jones"
> <geo### [at] galaxynetcom> wrote:
>
> >I would like to put in a list of 3D points and finish up with a set of
> >triangles that I can massage into a mesh_triangle set.
> >
> >I would like to try this as an alternate to gridding the data and then
> >displaying as a height_field.
> >
> >I am using MS Windows and see several progs for Unix based systems but
not
> >MS.W.
>
> Can you please send me the links to these Unix programs (or the
> programs if you can fit everything in under 500k)? I'll check and see
> if any of them does what you want, then maybe recompile it for Win32
> if I can.
>
>
> Peter Popov
> pet### [at] usanet
> ICQ: 15002700

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On Fri, 18 Feb 2000 16:54:38 -0800, "David Vincent-Jones"
<geo### [at] galaxynetcom> wrote:

>Peter;
>
>Here are 2 that may be worth looking at.
>
>I used a search on 'Delaunay and Triangular ' to find them.
>
>The second item has quite a good description of the process

I'll look into it.


Peter Popov
pet### [at] usanet
ICQ: 15002700

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Ken <tyl### [at] pacbellnet> writes:

> David Vincent-Jones wrote:
> > 
> > I would like to put in a list of 3D points and finish up with a set of
> > triangles that I can massage into a mesh_triangle set.
> 
> It sounds like you are describing what is known as a point cloud. Each
> reference point of data is given as a single 3D coordinate rather than
> a list of vertices that most 3D formats use. I too have looked for
> software that will accomplish what you are looking for and have found
> a definate lack of software to do this on any platform. I am sure it is
> possible to write software to do this but you would have to have a strict
> set of rules for the point cloud so that the software can logically connect
> the individual points for you. Otherwise you will get a meaningless
> jumble of triangles.

The reconstruction of a surface from a point cloud is subject to current
research. That's why it is not too surprising that no free all purpose tool 
exists for this task. 

Thomas

-- 
http://thomas.willhalm.de/ (includes pgp key)

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Thomas Willhalm wrote:
> 
> Ken <tyl### [at] pacbellnet> writes:
> 
> > David Vincent-Jones wrote:
> > >
> > > I would like to put in a list of 3D points and finish up with a set of
> > > triangles that I can massage into a mesh_triangle set.
> >
> > It sounds like you are describing what is known as a point cloud. Each
> > reference point of data is given as a single 3D coordinate rather than
> > a list of vertices that most 3D formats use. I too have looked for
> > software that will accomplish what you are looking for and have found
> > a definate lack of software to do this on any platform. I am sure it is
> > possible to write software to do this but you would have to have a strict
> > set of rules for the point cloud so that the software can logically connect
> > the individual points for you. Otherwise you will get a meaningless
> > jumble of triangles.
> 
> The reconstruction of a surface from a point cloud is subject to current
> research. That's why it is not too surprising that no free all purpose tool
> exists for this task.
> 
> Thomas
> 
> --
> http://thomas.willhalm.de/ (includes pgp key)

The closest thing is probably finding a 'convex hull'
You could look at 
http://www.geom.umn.edu/software/qhull/

PoD.

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