If I have a given function for an isosurface (e.g. x*x+y*y-1), what 
variable substitution do I have to do to repeat this surface, say along 
the z-axis every 2 POV-Units?
I want to achieve sth. like the "texture" in Tor Olav's "Entering" 
(http://news.povray.org/povray.binaries.images/33512/).

I tried to substitute x using mod(x,2), and I also tried using 
sin(x*something) and both of them came near to what I want, but not 
really :)

Thanks for your Help
Florian

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tor### [at] torfboldcom news:3fd86bf4$1@news.povray.org

> (http://news.povray.org/povray.binaries.images/33512/).
> I tried to substitute x using mod(x,2), and I also tried using 
> sin(x*something) and both of them came near to what I want, but not 
> really :)

It realy should work imho - sin and/or mod, maybe togeather with abs

simple grid was afair like

max(  pow(sin(x),40)  + pow(sin(y),40)  )

-- 
#macro g(U,V)(.4*abs(sin(9*sqrt(pow(x-U,2)+pow(y-V,2))))*pow(1-min(1,(sqrt(
pow(x-U,2)+pow(y-V,2))*.3)),2)+.9)#end#macro p(c)#if(c>1)#local l=mod(c,100
);g(2*div(l,10)-8,2*mod(l,10)-8)*p(div(c,100))#else 1#end#end light_source{
y 2}sphere{z*20 9pigment{function{p(26252423)*p(36455644)*p(66656463)}}}//M

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Wasn't it Florian Brucker who wrote:
>If I have a given function for an isosurface (e.g. x*x+y*y-1), what 
>variable substitution do I have to do to repeat this surface, say along 
>the z-axis every 2 POV-Units?
>I want to achieve sth. like the "texture" in Tor Olav's "Entering" 
>(http://news.povray.org/povray.binaries.images/33512/).
>
>I tried to substitute x using mod(x,2), and I also tried using 
>sin(x*something) and both of them came near to what I want, but not 
>really :)

Try   function { F(mod(abs(x),2)-1, y, z) }


-- 
Mike Williams
Gentleman of Leisure

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Wasn't it Mike Williams who wrote:
>Wasn't it Florian Brucker who wrote:
>>If I have a given function for an isosurface (e.g. x*x+y*y-1), what 
>>variable substitution do I have to do to repeat this surface, say along 
>>the z-axis every 2 POV-Units?
>>I want to achieve sth. like the "texture" in Tor Olav's "Entering" 
>>(http://news.povray.org/povray.binaries.images/33512/).
>>
>>I tried to substitute x using mod(x,2), and I also tried using 
>>sin(x*something) and both of them came near to what I want, but not 
>>really :)
>
>Try   function { F(mod(abs(x),2)-1, y, z) }

Or, if your original function is asymmetric in x, and you want the
result not to be reflected in the x axis you can try

  function { F(mod((x+999),2)-1,y,z) }

which repeats the part of the isosurface between x=-1 and x=1 or try

  function { F(mod((x+1000),2),y,z) }

which repeats the part of the isosurface between x=0 and x=2


-- 
Mike Williams
Gentleman of Leisure

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thanks guys, I think that'll solve my problems.

Greetings
Florian

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