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Can anyone explain why crackle is so slow
when used as a pigment function in isosurfaces.
The following isosurface renders at 8 pps.
Any suggestions on speeding this up? I tried rendering a crackle
pigmented plane and using it as an image_map in an isosurface,
but it was just as slow
#declare Crackle2=
function {pigment {crackle solid}}
isosurface {
function {y - Crackle2(x*3,0,z*3)*0.4}
threshold 0
method 2
eval
contained_by {box {<-8,-1,-8>,<8,3,8>}}
pigment {rgb 1}
}
Thanks
Gail
--
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* gsh### [at] monotix co za * System.dat not found. *
* http://www.rucus.ru.ac.za/~gail/ * Reformat hard drive Y)es O)k *
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Gail Shaw wrote:
>
> Can anyone explain why crackle is so slow
> when used as a pigment function in isosurfaces.
> The following isosurface renders at 8 pps.
>
> Any suggestions on speeding this up? I tried rendering a crackle
> pigmented plane and using it as an image_map in an isosurface,
> but it was just as slow
>
"crackle solid" has an infinite max_gradient, and the higher the
max_gradient, the slower the render. If you really need it to be
"solid", you might want to specify max_gradient manually, rather than
using eval (but of course, if you lower it too much artifacts may
appear).
--
* Abandon the search for truth, * mailto:ber### [at] iname com
* Settle for a good fantasy. * http://www.enst.fr/~jberger
*********************************
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Gail Shaw <gsh### [at] monotix co za> wrote:
: eval
That slows down a lot.
Put a max_gradient by hand.
--
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/
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"Warp" <war### [at] tag povray org> wrote in message
news:3a1d250f@news.povray.org...
> Gail Shaw <gsh### [at] monotix co za> wrote:
> : eval
>
> That slows down a lot.
> Put a max_gradient by hand.
I've been meaning to ask, how does one calculate a max_gradient? I've
been just guessing and testing. But it seems that some folk have specific
values that they use.
In other words, mine always end up as round numbers or simple divisions
(2.5, 10, 3.25) but I have seen other people who use things like 12.23937
which leads me to think that they did some sort of calculation.
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"Bill DeWitt" <the### [at] earthlink net> wrote in message
news:3a1d464d@news.povray.org...
....
> which leads me to think that they did some sort of calculation.
>
Dunno what anyone else does - when I'm happy with the shape of my iso I set
a ridiculously high max_gradient, use eval, and then remove eval and replace
max_gradient with the value returned by eval. I tend to add 0.1 to the eval
"just in case".
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"Tom Melly" <tom### [at] tomandlu co uk> wrote :
>
> Dunno what anyone else does - when I'm happy with the shape of my iso I
set
> a ridiculously high max_gradient, use eval, and then remove eval and
replace
> max_gradient with the value returned by eval.
Huh...? "returned"? I guess I need to pay more attention to the message
window...
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Bill DeWitt <the### [at] earthlink net> wrote:
: Huh...? "returned"? I guess I need to pay more attention to the message
: window...
When you use eval, the calculated max_gradient is output to the message
window when the rendering finishes. Somewhere there.
--
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/
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From: Marc-Hendrik Bremer
Subject: Re: Crackle pigment in functions
Date: 23 Nov 2000 13:50:39
Message: <3a1d66ff@news.povray.org>
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BTW: If you have more Isos with "eval" in the scene - there is no output of
the max_gradient , is it?
Marc-Hendrik
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Marc-Hendrik Bremer wrote:
>
> BTW: If you have more Isos with "eval" in the scene - there is no output of
> the max_gradient , is it?
>
There is (in my IsoWood demo, you get whole pages of max_gradients :-)
BTW, i had several situations when 'eval' was faster than a specified
max_gradient, don't know why though.
Christoph
--
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Homepage: http://www.schunter.etc.tu-bs.de/~chris/
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news:3A1D08D7.54E75832@enst.fr...
> Gail Shaw wrote:
> >
> "crackle solid" has an infinite max_gradient, and the higher the
> max_gradient, the slower the render. If you really need it to be
> "solid", you might want to specify max_gradient manually, rather than
> using eval (but of course, if you lower it too much artifacts may
> appear).
>
Thanks, renders in 3 min without eval, looks terrible though.
I'm trying for a rough crystal look and normal crackle isn't quite
what I'm looking for.
Gail
--
********************************************************************
* gsh### [at] monotix co za * System.dat not found. *
* http://www.rucus.ru.ac.za/~gail/ * Reformat hard drive Y)es O)k *
********************************************************************
* If at first you don't succeed, call it version 1.0 *
********************************************************************
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