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3 Nov 2024 08:26:34 EST (-0500)
  Isosurface tutorial (Message 1 to 8 of 8)  
From: Mike Williams
Subject: Isosurface tutorial
Date: 1 Apr 2000 04:49:41
Message: <y6TnDFAv$Y54Ew1u@econym.demon.co.uk>
I've put together a little bit of an unofficial tutorial about
isosurfaces at

http://www.econym.demon.co.uk/isotut/

Hope you like it.

-- 
Mike Williams
Gentleman of Leisure


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From: Warp
Subject: Re: Isosurface tutorial
Date: 2 Apr 2000 13:54:33
Message: <38e78958@news.povray.org>
Not bad.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/


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From: Robert Jefferson
Subject: Re: Isosurface tutorial
Date: 2 Apr 2000 20:49:10
Message: <38e7ea86$1@news.povray.org>
very good pigment stuff

--
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Click here for Free Video!!
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"Warp" <war### [at] tagpovrayorg> wrote in message
news:38e78958@news.povray.org...
>   Not bad.
>
> --
> main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
> ):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/


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From: Pabs
Subject: Re: Isosurface tutorial
Date: 5 Apr 2000 22:39:37
Message: <38EBF909.A986DE48@hotmail.com>
You wouldn't happen to know anything about isosurface heightfeilds BTW.


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From: Chris Huff
Subject: Re: Isosurface tutorial
Date: 6 Apr 2000 11:37:41
Message: <chrishuff_99-89E2D8.10401006042000@news.povray.org>
In article <38EBF909.A986DE48@hotmail.com>, Pabs <pab### [at] hotmailcom> 
wrote:

> You wouldn't happen to know anything about isosurface heightfeilds BTW.

Start with a plane and a pigment function:
#declare CrackleFn =
function {
    pigment {crackle ramp_wave
        color_map {[0 rgb 0][1 rgb 1]}
    }
}
function {y}

And subtract the pigment function from the plane function, so it is 
raised depending on the value of the pigment. There are two ways to do 
this, one which allows overhangs and separated pieces of the height 
field(because it makes the pattern function dependant on y):
function {y - CrackleFn(x,y,z)}

and one which behaves like the usual height field, with no overhangs:
function {y - CrackleFn(x,0,z)}

In the isosurface, use a threshold of 0 and bound with a box from 
<0,0,0> to <1,1,1> if you want to make a direct substitution for a 
height_field primative.
isosurface {
    function {y - CrackleFn(x,0,z)}
    threshold 0
    eval
    contained_by {box {<0,0,0>, <1,1,1>}}
}

-- 
Christopher James Huff - Personal e-mail: chr### [at] yahoocom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
Web page: http://chrishuff.dhs.org/


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From: Pabs
Subject: Re: Isosurface tutorial
Date: 6 Apr 2000 21:43:12
Message: <38ED3D51.C3438F7B@hotmail.com>
Thanks heaps


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From: Pabs
Subject: Re: Isosurface tutorial
Date: 9 Apr 2000 21:23:53
Message: <38F12D48.C366F9FB@hotmail.com>
> #declare CrackleFn =
> function {
>     pigment {crackle ramp_wave
>         color_map {[0 rgb 0][1 rgb 1]}
>     }
> }
> function {y}

Sorry - what about if I want to use a gif/tga, just like in a proper hf -
what pigment should I use for this


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From: Chris Huff
Subject: Re: Isosurface tutorial
Date: 9 Apr 2000 21:32:02
Message: <chrishuff_99-C220A6.20343709042000@news.povray.org>
In article <38F12D48.C366F9FB@hotmail.com>, Pabs <pab### [at] hotmailcom> 
wrote:

> Sorry - what about if I want to use a gif/tga, just like in a proper hf -
> what pigment should I use for this

Use an image map in the pigment...just don't forget to turn on 
interpolation.
#declare imagePigmentFn =
function {
    pigment {
        image_map {png "image.png"
            map_type 0
            interpolate 2
        }
        rotate x*90 // because image_maps are projected in the xy plane
    }
}

-- 
Christopher James Huff - Personal e-mail: chr### [at] yahoocom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
Web page: http://chrishuff.dhs.org/


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