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19 Nov 2024 02:21:18 EST (-0500)
  -x*x/x*x-1 (Message 1 to 6 of 6)  
From: H  David Young
Subject: -x*x/x*x-1
Date: 31 Jan 2002 04:04:47
Message: <3c5908af@news.povray.org>
I was working on my calculus when I came across this function and thought
that it would be interesting as a three dimensional rendering.  I placed
spheres according to the equation and then rotated them around.  There are
5796 spheres in this picture;  I have tried as many as 100 000, but found
that the 'surface' did not look as good as the points.  This picture took a
couple seconds to parse and about 20 seconds to render (PIII 700).  I placed
a simple texture on each sphere to give it a less rendered look.  I like
what came out of it, since it was so simple to make and required very little
code.  I hope to find more interesting functions, and maybe try to some
truly three dimensional graphs, rather than rotating two dimensional ones.
As always any comments, good or bad, nice or mean, are welcome.

H. David Young


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From: Grey Knight
Subject: Re: -x*x/x*x-1
Date: 31 Jan 2002 06:02:25
Message: <3C592439.1553484F@namtar.qub.ac.uk>
Cool! Try putting it in an isosurface (if I was at home instead of at
uni I'd do it myself)
function{ -x*x/x*x-1-y } outta do the trick (note the final "-y" term;
this is essential for rendering equations of the form y=f(x)

-- 
signature{
  "Grey Knight" contact{ email "gre### [at] yahoocom" }
  site_of_week{ url "http://digilander.iol.it/jrgpov" }
}


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From: Hershel Robinson
Subject: Re: -x*x/x*x-1
Date: 1 Feb 2002 05:38:33
Message: <3c5a7029$1@news.povray.org>
> As always any comments, good or bad, nice or mean, are welcome.

I think it's beautiful.  As a matter of fact, last time I visited home, I
almost took back one of my mother's Calculus books (she teaches high school
math) just to refresh myself on these interesting 3D functions.  I would
love to see more. :)

Hershel


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From: Christopher James Huff
Subject: Re: -x*x/x*x-1
Date: 1 Feb 2002 20:42:33
Message: <chrishuff-9DAAF2.20434901022002@netplex.aussie.org>
Looks good...but it looks more like -x*x/(x*x - 1) to me. -x*x/x*x - 1 
is the same as -1 - 1, or just -2.
An isosurface wouldn't be hard, but the radial (or circular, depending 
on how you look at it) strings of spheres are interesting.
The spheres get kind of smudgy and fuzzy off in the distance...it looks 
like you used focal blur, is that what causes the smudges?

Just wondering, what does this function have to do with calculus?

-- 
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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From: H  David Young
Subject: Re: -x*x/x*x-1
Date: 1 Feb 2002 21:59:25
Message: <3c5b560d$1@news.povray.org>
It is actually:  yPos = ((xPos*xPos)/((xPos*xPos)-1)), I just
said -x*x/x*x-1 to keep it simple.  As for the focal blur, I didn't use
anything other than the basic shape, and a simple texture (and I think it
was the texture that caused the blur, I noticed that too).  The reason I
mentioned calculus was because this was an example in my calculus text book.
The whole scene, if you are interested was:

camera {
  location  <1,1,-5>
  look_at   <0,-1.5,0>
}

light_source { <4,1,-6> rgb <1,1,1> }
light_source { <0,-1,0> rgb <.5,.2,.2> }

#declare xPos = 0;

#while (xPos < 16)

 #declare yPos = ((xPos*xPos)/((xPos*xPos)-1));
 #declare rot = 0;

 #while (rot < 360)
  sphere {
   <xPos,-yPos,0>, .1
   texture {
    pigment {
     bozo
     turbulence 1
     colour_map {
      [0.0 rgb <.9,0,0>]
      [0.5 rgb <.7,0,0>]
      [1.0 rgb <.9,0,0>]
     }
    }
    finish {
     specular .2
     roughness .2
    }
    scale .06
   }
   rotate <0,rot,0>
  }
  #declare rot = rot + 10;
 #end

 #declare xPos = xPos + .1;
#end


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From: Bill Naylor
Subject: Re: -x*x/x*x-1
Date: 3 Feb 2002 08:19:22
Message: <3C5D37F4.6101556@hotmail.com>
This image reminded me of some while loop practice I did. I must admit that the
digression has continued for quite some time.  I've got more ribbons and worms
than you can shake a stick at.  Here's an early one.

Comments welcome!

Thanks for all the inspiring images!!

Bill


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