I'm not sure if this would speed things up (maybe someone has already done
this?) but here's my idea:

I think it should be possible to write a macro that would take an isosurface
function and make a low poly mesh from that. You should also then be able to
alter the quality higher or lower according to your need. The purpose of this
would be two-fold: Quick preview of isosurfaces and making it possible to export
iso-surfaces to other 3d formats as a mesh.

Has any-one done anything like this before?

Comments?

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- Nekar

http://nekar_xenos.tripod.com/metanoia/



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You mean like Ingo's param.inc? It generates meshes from isosurfaces, but it
needs them to be in parametric form. I toyed with the idea of parametrizing
(does such term exist in the English language?) equations for a while, but
it is definitely not a trivial task depending on the equation.

Ruy

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"Ruy" <ruy### [at] hipernetcombr> wrote in message news:3c07719f$1@news.povray.org...
> You mean like Ingo's param.inc? It generates meshes from isosurfaces, but it
> needs them to be in parametric form. I toyed with the idea of parametrizing
> (does such term exist in the English language?) equations for a while, but
> it is definitely not a trivial task depending on the equation.
>
> Ruy
>

Where can I get Ingo's param.inc? What is parametric form?

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- Nekar

http://nekar_xenos.tripod.com/metanoia/



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Nekar Xenos wrote:
> 
> I'm not sure if this would speed things up (maybe someone has already done
> this?) but here's my idea:
> 
> I think it should be possible to write a macro that would take an isosurface
> function and make a low poly mesh from that. You should also then be able to
> alter the quality higher or lower according to your need. The purpose of this
> would be two-fold: Quick preview of isosurfaces and making it possible to export
> iso-surfaces to other 3d formats as a mesh.
> 
> Has any-one done anything like this before?

See:

From: "Mael" <mae### [at] hotmailcom>
Newsgroups: povray.general
Subject: marching cube macro
Date: Thu, 27 Sep 2001 17:00:13 +0200

and also Warp's tesselation patch.  

It is surely not a good way for quick preview renders since generating the
mesh takes quite some time no matter what method you use.

Another problem is that using a method generating meshes with constant
resolution results in incredibly large meshes with high resolutions. 
Algorithms which produce meshes with variable (curvature dependant)
resolution are fairly complicated and usually are quite slow too.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

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> Where can I get Ingo's param.inc?

It's been posted on povray.binaries.scene-files on September 13.

> What is parametric form?

The parametric form is a way to represent equations where each individual
coordinate (x, y and z) are represented as functions of two parameters
(usually represented by u and v)

So, instead of having F(x, y, z) as your function, you would havem three
separate equations:

x = f(u,v)
y = g(u,v)
z = h(u,v)

Where f, g and h are the parametric equations.

Finding f(u,v), g(u,v) and h(u,v) based on F(x,y,z), though, may get to be
quite an unsurmountable task...

Ruy

>
> --
> - Nekar
>
> http://nekar_xenos.tripod.com/metanoia/
>
>
>
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"Christoph Hormann" <chr### [at] gmxde> wrote in message
news:3C077536.E4B0E0D0@gmx.de...
>
>
> Nekar Xenos wrote:
> >
> > I'm not sure if this would speed things up (maybe someone has already done
> > this?) but here's my idea:
> >
> > I think it should be possible to write a macro that would take an isosurface
> > function and make a low poly mesh from that. You should also then be able to
> > alter the quality higher or lower according to your need. The purpose of
this
> > would be two-fold: Quick preview of isosurfaces and making it possible to
export
> > iso-surfaces to other 3d formats as a mesh.
> >
> > Has any-one done anything like this before?
>
> See:
>
> From: "Mael" <mae### [at] hotmailcom>
> Newsgroups: povray.general
> Subject: marching cube macro
> Date: Thu, 27 Sep 2001 17:00:13 +0200
>
> and also Warp's tesselation patch.
>

The link to the marching cube macro is dead. Can anyone send it to me maybe?



--
- Nekar

http://nekar_xenos.tripod.com/metanoia/


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