Christopher James Huff wrote:
>
> However, you are aware of the patent on the marching cubes algorithm,
> aren't you?

I'll be happy to set up a distribution point for the illegal part of
this patch here in Finland where silly software patents are worth nothing.
It'll be perfectly legal to host it here. I'll have to check with some
law experts first though but it worked for some patented mp3 audio encoder.
The naughty bits were hosted here :)


_____________
Kari Kivisalo

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in news:3C745C3B.13F5BDF5@engineer.com Kari Kivisalo wrote:

> I'll be happy to set up a distribution point for the illegal part of
> this patch here in Finland where silly software patents are worth
> nothing. 

You could also ask the owner of the patent if it's ok to use it in POV-Ray 
and patches. Obtaining a license doesn't always mean paying for it. As far 
as I know it's already in use with "no cost, available source" software: 
VTK
http://www.kitware.com/
http://public.kitware.com/cgi-bin/vtkfaq?req=show&file=faq07.001.htp
http://public.kitware.com/cgi-bin/vtkfaq?req=show&file=faq07.005.htp

Ingo

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Christopher James Huff wrote:
> 
> Looks good...while not perfect, the meshes should work fine for things
> like proximity calculations. I will finally be able to finish my glow
> and proximity pattern patches. When are you planning to release source
> code?
 
When really finished... and I just get answers which mean it will be later, due
to more development that are still to be done regarding the texture.


> However, you are aware of the patent on the marching cubes algorithm,
> aren't you?

Please provide reference to such patent, including date and description.

-- 
Non Sine Numine
http://grimbert.cjb.net/
Puis, s'il advient d'un peu triompher, par hasard,

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I must say, I find it kind of strange. There are errors in all examples of
the tesselated POV-LOGO. Will the marching triangle algoritm solve this
problem?

There exsist other algoritms - I'm not able to understand such high
mathematics, but have you read the various good explanations on the Internet
about (for example) Delaunay triangulation? It's widely used. I never heard
of marching cubes/triangles before.

Wouldn't it be easier to adapt an already written sourcecode in C ?


Regards,
Hugo

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In article <3C751726.20584A5E@atosorigin.com>,


> > However, you are aware of the patent on the marching cubes algorithm,
> > aren't you?
> 
> Please provide reference to such patent, including date and description.

These are the two patents listed in the comp.graphics.algorithms FAQ:
http://www.delphion.com/details?pn=US04710876__
http://www.delphion.com/details?pn=US04885688__

http://www.google.com/search?hl=en&q=marching+cubes+patent

-- 
Christopher James Huff <chr### [at] maccom>
POV-Ray TAG e-mail: chr### [at] tagpovrayorg
TAG web site: http://tag.povray.org/

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In article <3c752dc7$1@news.povray.org>, "Hugo" <hua### [at] post3teledk> 
wrote:

> I must say, I find it kind of strange. There are errors in all examples of
> the tesselated POV-LOGO. Will the marching triangle algoritm solve this
> problem?

You need to generate points on the surface of the object. All these 
methods can "miss" sharp edges and points...there is no way to tell them 
you need points at the tip of a cone, you will need to use a special 
algorithm for cones or just use such a high resolution mesh that the 
errors are invisible.


> There exsist other algoritms - I'm not able to understand such high
> mathematics, but have you read the various good explanations on the Internet
> about (for example) Delaunay triangulation? It's widely used. I never heard
> of marching cubes/triangles before.

As far as I can tell (I can't find any clear explanations of it), it 
takes a group of points as input and produces a surface from them. A 
surface, not necessarily the surface that produced the points. And you 
still have the problem of generating the points on edges.


> Wouldn't it be easier to adapt an already written sourcecode in C ?

Not really, because the POV patch will have to use existing data types 
and code in POV-Ray. Having source code would make it easier to write 
though.

-- 
Christopher James Huff <chr### [at] maccom>
POV-Ray TAG e-mail: chr### [at] tagpovrayorg
TAG web site: http://tag.povray.org/

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> As far as I can tell (I can't find any clear explanations of it), it
> takes a group of points as input and produces a surface from them. A
> surface, not necessarily the surface that produced the points. And you
> still have the problem of generating the points on edges.

Thanks for your input. My understanding - though limited, but I did read
articles on delaunay triangulation some time ago - is that they generate a
very good mesh, matching the original form precisely but with few triangles.
The idea is that you trace enough points to have a very precise input for
the delaunay triangulation, which will then generate the final mesh by
carefully choosing the most important points.

I can try to find again the articles I read, if this will be useful.

Regards,
Hugo

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Is the purpose of your patch to produce meshes from POV solid objects?

John Haiducek

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John Haiducek wrote:
> 
> Is the purpose of your patch to produce meshes from POV solid objects?

Solid Finite Bounded Object: Yes.

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Christopher James Huff wrote:

> These are the two patents listed in the comp.graphics.algorithms FAQ:
> http://www.delphion.com/details?pn=US04710876__

No status for that one. 
What's the default duration for a US patent ?
From the first page description (which is all I can read), it seems
to patent an idea as well as an apparatus.
I have no apparatus and patent on idea are not applicable in my country.
 (Moreover, computer program are not protected by patent here, but by 
 author's right)
At most, 2 of the 6 methods for tesselation in my code might be subject
 to importation-in-US-restriction, the same two that I do not write the arrays
 myself (the code is mine 100%, but I copy some data arrays from a web page).
So far, I would have to check the nationality and clearance of Heller and Bourke,
the two people which provide the data arrays.

> http://www.delphion.com/details?pn=US04885688__
That one is Expired. <Plonk>

Side note: maybe it's time to enforce an importation-banning rule for the US!
Just like the US have an exportation-banning rule regarding crypto and other things!

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