I have to admit that one week ago I played 
around with MegaPOV's eval_pattern to see
if I could make a 3D-pattern "visible" with
a blob.

The image enclosed is one of the results 
from experimenting with the bozo pattern.

The code I used to make it did not work 
quite as I expected, so I didn't like the 
result back then. 

But I have had a second look at the image,
and now I think I like it.


Btw.: 

Is there a way in MegaPOV to have a 
"pattern surface" ? (I.e. make the surface
of a 3D-shape appear where a pattern have 
a certain threshold value.)


Tor Olav
-- 
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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Attachments:
Download 'blobpattern02_.jpg' (24 KB)

Preview of image 'blobpattern02_.jpg'

That's really lava-lampesque.

You can use a pigment function to define an isosurface.

#define pigfunc = funcion{pigment{bozo color_map{[0 rgb 1][1 rgb 0]}};

isosurface{
    function{pigfunc(x*xfactor,y*yfactor,z*zfactor)*Some_factor}
.
.
.
}


--


http://www.capital.net/~hhawkins


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"Tor Olav Kristensen" <tor### [at] hotmailcom> wrote :
>
> Is there a way in MegaPOV to have a
> "pattern surface" ? (I.e. make the surface
> of a 3D-shape appear where a pattern have
> a certain threshold value.)

    Um... Isosurface? #declare the pattern as a function and use it that
way? Maybe I don't understand the question...

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> #define pigfunc = funcion{pigment{bozo color_map{[0 rgb 1][1 rgb 0]}};

I mean #declare of coarse!

(that's a c/c++ism)


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Fase clock animate dude.

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Cheers
Steve              email mailto:ste### [at] zeroppsuklinuxnet

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In article <39E103B3.7EE3B0A9@hotmail.com>, Tor Olav Kristensen 
<tor### [at] hotmailcom> wrote:

> Is there a way in MegaPOV to have a 
> "pattern surface" ? (I.e. make the surface
> of a 3D-shape appear where a pattern have 
> a certain threshold value.)

The isosurface is perfect for this...

#declare Func =
function {
    pigment {bozo color_map {[0 rgb 0][1 rgb 1]}}
}


isosurface {
    function {Func(x, y, z)}
    threshold 0.5
    contained_by {
        box {<-1,-1,-1>, < 1, 1, 1>}
    }
}

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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Tor Olav Kristensen wrote:
> ...
> Is there a way in MegaPOV to have a
> "pattern surface" ? (I.e. make the surface
> of a 3D-shape appear where a pattern have
> a certain threshold value.)

Thank you all for fast replies.

You've helped me to do what I wanted.

But I don't understand why one has to involve
pigments to determine a surface.

Why can I not define the function like this ?

function {
  eval_pattern(bozo scale <1, 1, 1>/4, x + y + z)
}

Please explain.


Enclosed are an image I just made.
I love isosurfaces !


Tor Olav
-- 
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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Attachments:
Download 'bozo.jpg' (48 KB)

Preview of image 'bozo.jpg'

In article <39E123D3.1C989ED3@hotmail.com>, Tor Olav Kristensen 
<tor### [at] hotmailcom> wrote:

> Why can I not define the function like this ?
> 
> function {
>   eval_pattern(bozo scale <1, 1, 1>/4, x + y + z)
> }
> 
> Please explain.

Because nobody has added the eval_pattern() function to isosurface 
functions yet. Oh, and it wouldn't be "x + y + z", it looks like you 
meant "x, y, z". :-)
The eval_pattern() function would probably be a little bit faster than a 
pigment function, and certainly easier to use, but I don't plan on 
trying to add it to isosurfaces until a MegaPOV based on POV 3.5 is 
released. Adding an isosurface function is a bit more complex than 
ordinary functions, and I want to wait until the isosurface code is 
cleaned up and organized better.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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Chris Huff wrote:

> In article <39E123D3.1C989ED3@hotmail.com>, Tor Olav Kristensen
> <tor### [at] hotmailcom> wrote:
>
> > Why can I not define the function like this ?
> >
> > function {
> >   eval_pattern(bozo scale <1, 1, 1>/4, x + y + z)
> > }
> >
> > Please explain.
>
> Because nobody has added the eval_pattern() function to isosurface
> functions yet. Oh, and it wouldn't be "x + y + z", it looks like you
> meant "x, y, z". :-)

Yes you're right. I think I misunderstood that part.


> The eval_pattern() function would probably be a little bit faster than a
> pigment function, and certainly easier to use, but I don't plan on
> trying to add it to isosurfaces until a MegaPOV based on POV 3.5 is
> released. Adding an isosurface function is a bit more complex than
> ordinary functions, and I want to wait until the isosurface code is
> cleaned up and organized better.

Ahh... I thought that any float expression would do. -Sorry.

Has the added complexity anything to do with the derivatives
of these iso-functions ?


Tor Olav
--
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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Steve wrote:

> Fase clock animate dude.

What do you mean ?
That I should make an animation of it ?

Have anyone done any animations with iso-
surfaces that changes their shapes according to
a 3D-pattern that has it's different parameters
changed slowly ?

I'll have to try that some day.


Tor Olav
--
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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