POV-Ray : Newsgroups : povray.unofficial.patches : Parametrics and superellipsoids Server Time
1 Nov 2024 11:15:49 EDT (-0400)
  Parametrics and superellipsoids (Message 1 to 7 of 7)  
From: Greg M  Johnson
Subject: Parametrics and superellipsoids
Date: 3 Jan 2001 08:44:32
Message: <3A532B6E.DFAA8DED@my-dejanews.com>
Please see a question I raised in p.b.i...


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From: Chris Huff
Subject: Re: Parametrics and superellipsoids
Date: 3 Jan 2001 17:42:01
Message: <chrishuff-236E91.17433103012001@news.povray.org>
In article <3A532B6E.DFAA8DED@my-dejanews.com>, 
gre### [at] my-dejanewscom wrote:

> Please see a question I raised in p.b.i...

Hmm...why, exactly, are you trying to make a superellipsoid with a 
parametric? A simple isosurface would be much easier, and would work 
with CSG, which parametrics apparently don't do well...

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><


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From: Greg M  Johnson
Subject: Re: Parametrics and superellipsoids
Date: 4 Jan 2001 09:10:45
Message: <3A548313.DB93E0D6@my-dejanews.com>
Chris Huff wrote:

> Hmm...why, exactly, are you trying to make a superellipsoid with a
> parametric? A simple isosurface would be much easier, and would work
> with CSG, which parametrics apparently don't do well...

I had delusions  of grandeur of being able to tweak existing code and
make some really cool new object...   An isosurface?--hmm, thanks will
try that instead...


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From: Gilles Tran
Subject: Re: Parametrics and superellipsoids
Date: 4 Jan 2001 09:20:11
Message: <3A548738.DF1DB1B2@inapg.inra.fr>
"Greg M. Johnson" wrote:

> I had delusions  of grandeur of being able to tweak existing code and
> make some really cool new object...   An isosurface?--hmm, thanks will
> try that instead...

Superellipsoids are nicely done by isosurfaces. Below is some code for an
icecube. Works great with photon mapping.

G.

#declare IceTxt=material{
 texture { pigment { rgbt<189/255,194/255,197/255,1>}  finish { ambient 0
specular 1 roughness 0.0001 reflection 0.1}
 }
 interior{
        ior 1.309
        fade_power 2 fade_distance 2.5
        media {
                        emission col2*0.3
                        method 2
                        density{boxed turbulence 1 color_map{[0 Black][1
White*2]}}
                        scale 0.7
         }
 }
}
#declare e=0.05;
#declare n=0.05;
#declare IceCube=isosurface {
 function {( abs(x)^(2/e)+abs(y)^(2/e))^(e/n)+abs(z)^(2/n)-1 +
1.2*noise3d(x*1.22,y*1.2,z*1.2)}
 contained_by { box { -1, 1 } }
 threshold 0
 method 2  max_gradient 14
 hollow
 material{IceTxt}
}


--

**********************
http://www.oyonale.com
**********************
Graphic experiments
Pov-ray gallery


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From: Greg M  Johnson
Subject: Re: Parametrics and superellipsoids
Date: 4 Jan 2001 13:37:22
Message: <3A54C17B.478C04D1@my-dejanews.com>
Thanks!

Gilles Tran wrote:

>                        emission col2*0.3

BTW col2 is undefined.

> abs(x)^(2/e)

The funniest thing is that I saw many different formulas for s-e's on the web
and when I saw the above represented with a funny "2 bar over e"  this math
idiot thought it was something more complicated than mere division.


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From: Christoph Hormann
Subject: Re: Parametrics and superellipsoids
Date: 4 Jan 2001 13:51:38
Message: <3A54C63B.1D5CF126@gmx.de>
"Greg M. Johnson" wrote:
> 
> The funniest thing is that I saw many different formulas for s-e's on the web
> and when I saw the above represented with a funny "2 bar over e"  this math
> idiot thought it was something more complicated than mere division.

There is the formular in the povray 3.1 docu, but IMO it's not necessary
for isosurface superellipsoids, because there already is a predefined
function, which, according to the megapov docu, computes the same:

f = (|x|^(2/P0) + |y|^(2/P0)) ^ (P0/P1) + |z|^(2/P1) - 1 = 0 

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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From: Gilles Tran
Subject: Re: Parametrics and superellipsoids
Date: 4 Jan 2001 13:59:03
Message: <3A54C894.248C4913@inapg.inra.fr>
"Greg M. Johnson" wrote:

> BTW col2 is undefined.

Sorry, try this one :
#declare col2=rgb<210,220,220>/255;
It really depends on the scene the ice cube is of course.

G.

--

**********************
http://www.oyonale.com
**********************
Graphic experiments
Pov-ray gallery


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