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From: Peter Popov
Subject: Equiation needed
Date: 23 Feb 1999 23:54:11
Message: <3c796fc0.8500773@news.povray.org>
Can anyone suggest an equation that gives the distance to a unit
circle lying in the x-z plane? It should look like an wood pattern
whose axis is not +z but a circle. Any ideas?

TIA.


---------
Peter Popov
ICQ: 15002700


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From: Gordon
Subject: Re: Equiation needed
Date: 26 Feb 1999 07:21:02
Message: <36d691ae.0@news.povray.org>
This is untested but I'm fairly sure it's right.

Assume X, Y, Z are the coords of the point in question.
D is the distance to the unit circle.

D = sqrt( pow(Y,2) + pow(sqrt(pow(X,2)+pow(Z,2))-1,2) )

Good luck.

Gordon
<gbe### [at] birdcameroncomau>

Peter Popov wrote in message <3c796fc0.8500773@news.povray.org>...
>Can anyone suggest an equation that gives the distance to a unit

>circle lying in the x-z plane? It should look like an wood pattern

>whose axis is not +z but a circle. Any ideas?

>

>TIA.

>

>

>---------

>Peter Popov

>ICQ: 15002700


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From: Fabien Mosen
Subject: Re: Equiation needed
Date: 28 Feb 1999 04:28:30
Message: <36D90D26.8E295D3@compuserve.com>
just a question : 
Your system date appear to be 24 Feb 2002.
The question is : what are the new features of POV-Ray 4.2 ?

Cheers,
Fabien.


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From: Spider
Subject: Re: Equiation needed
Date: 28 Feb 1999 04:49:40
Message: <36D90FCA.D09B5005@bahnhof.se>
Can you send a copy ???

Fabien Mosen wrote:
> 
> just a question :
> Your system date appear to be 24 Feb 2002.
> The question is : what are the new features of POV-Ray 4.2 ?
> 
> Cheers,
> Fabien.

-- 
//Spider 
( spi### [at] bahnhofse ) [ http://www.bahnhof.se/~spider/ ]
#declare life = rand(seed(42))*sqrt(-1);


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From: Peter Popov
Subject: Re: Equiation needed
Date: 1 Mar 1999 22:31:45
Message: <36db5077.29125891@news.povray.org>
On Sun, 28 Feb 1999 10:32:22 +0100, Fabien Mosen
<101### [at] compuservecom> wrote:

>just a question : 
>Your system date appear to be 24 Feb 2002.
>The question is : what are the new features of POV-Ray 4.2 ?
>
>Cheers,
>Fabien.

Reinstalled IE4.0 :)
At least now I know I am y2k prepared.

---------
Peter Popov
ICQ: 15002700


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From: Ilmari Karonen
Subject: Re: Equiation needed
Date: 8 Mar 1999 14:53:22
Message: <36e42ab2.0@news.povray.org>
Peter Popov wrote in message <3c796fc0.8500773@news.povray.org>...
>Can anyone suggest an equation that gives the distance to a unit
>circle lying in the x-z plane? It should look like an wood pattern
>whose axis is not +z but a circle. Any ideas?


If you have Superpatch, just use this macro (I just wrote this,
haven't tried it yet.)

#macro TorusWood ( Major )
  function { sqrt(x*x+y*y+z*z-Major*(2*sqrt(x*x+z*z)-Major)) }
#end

Put it where you'd normally have the name of the pattern, as in:

pigment {
  TorusWood( 5 )
  color_map {
    [0/3 color Red]
    [1/3 color Green]
    [2/3 color Blue]
    [3/3 color Red]
  }
}

Here are some other pattern macros:

// A torus-shaped density pattern, from which the above was derived.

#macro Toroidal ( Major ) // minor radius always 1
  function { max(0,1-sqrt(x*x+y*y+z*z-Major*(2*sqrt(x*x+z*z)-Major))) }
#end

// Two point-to-point cones around the y-axis, similar to the cylindrical
// pattern except the width of the cylinder at any point is the same as
// the y-coordinate value. (untested)

#macro Conical ( )
  function { max(0,1-sqrt(x*x+z*z)/abs(y)) }
#end

// A variable number of concentric cones, can be used with the radial
// pattern to create longitude-latitude lines on a sphere.

#macro Latitudes ( Frequency )
  #local Pi = pi; // don't ask, some "feature" of Superpatch
  function { Frequency*asin(y/sqrt(x*x+y*y+z*z))/Pi+Frequency/2 }
#end

More coming as soon as I finish my finals and have time for raytracing
again..

--
Ilmari Karonen (ilt### [at] scifi)
http://www.sci.fi/~iltzu/


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From: Matthew Bennett
Subject: Re: Equiation needed
Date: 9 Mar 1999 14:32:18
Message: <36e57742.0@news.povray.org>
Argh.. it this thread going to perpetually sit at the very top/bottom of our
newsreaders? :P

Matt


Peter Popov wrote in message <3c796fc0.8500773@news.povray.org>...
>Can anyone suggest an equation that gives the distance to a unit
>circle lying in the x-z plane? It should look like an wood pattern
>whose axis is not +z but a circle. Any ideas?
>
>TIA.
>
>
>---------
>Peter Popov
>ICQ: 15002700


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From: Margus Ramst
Subject: Re: Equiation needed
Date: 9 Mar 1999 15:16:44
Message: <36e581ac.0@news.povray.org>
No. His other post is at the bottom now. He has reached 2003 already...

Margus

Matthew Bennett wrote in message <36e57742.0@news.povray.org>...
>Argh.. it this thread going to perpetually sit at the very top/bottom of
our
>newsreaders? :P
>


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From: povray org admin team
Subject: Re: Equiation needed
Date: 10 Mar 1999 07:20:56
Message: <36e76475.9218281@news.povray.org>
"Margus Ramst" <mar### [at] peakeduee> wrote:

>No. His other post is at the bottom now. He has reached 2003 already...

Maybe he's doing some Y2K testing on POV-Ray ...


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From: Peter Popov
Subject: Re: Equiation needed
Date: 10 Mar 1999 11:08:34
Message: <36e79778.8542518@news.povray.org>
On Tue, 9 Mar 1999 19:30:42 -0000, "Matthew Bennett"
<ben### [at] btinternetcom> wrote:

>Argh.. it this thread going to perpetually sit at the very top/bottom of our
>newsreaders? :P
>
>Matt

Gee, guys, I am *really* sorry for the inconvenience! It all started
when I had to reinstall Internet Exploder 4 . It somehow messed up my
windoze clock and now it's gone completely nuts! I swear I set it back
to 1999 yesterday *and* this morning too, and two minutes ago it
showed 2003! I really hope it does not rewind to 1994 because windoze
95 might just as well kill itself as it will realise it will not have
been born yet. (Arrgh, verb tenses become a real problem when it comes
to time travelling). In fact that's already happened to me once -- all
files that were created/modified after the date indicated by the
system clock were swept away by a routine M$ ScumDisk check :(

Once again, I am really sorry for the date problem. I will make sure
the stupid mf (sorry) knows what date today is before I post anything.

---------
Peter Popov
ICQ: 15002700


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