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From: TinCanMan
Subject: Translate by turbulence
Date: 12 Jul 2002 10:12:53
Message: <3d2ee3e5$1@news.povray.org>
I don't think this is possible in 3.5 but I'll ask anyways (perhaps it'll
give someone an idea for a patch ;) )
This is a bit difficult to explain but:  I want to be able to translate an
object according to the turbulence value at its location.  Let's say we have
a plane with a checker pattern on it and we place a little ball at the
origin.  If we apply turbulence to the checker pattern, the point that was
originally at <0,0,0> is now somewhere else defined by the turbulence
parameters.  I would like to be able to move the sphere to this new
location, something along the lines of:

plane{y 0
     pigment{
       checker rgb 1 rgb 0
       turbulence 0.5
       octaves 5
       lambda 1.2
       omega .25
     }
}
#declare newpt =

sphere{0 0.1
   pigment{rgb <1,0,0>}
   translate turb_translate(
      <0,0,0> //point to read turbulence value from
      turbulence 0.5
      octaves 5
      lambda 1.2
      omega .25
   )
}

Does anyone have any idea on how this can be done in 3.5?

-tgq


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From:
Subject: Re: Translate by turbulence
Date: 12 Jul 2002 10:19:44
Message: <q2ptiucj8s1rouqpnt4td2ej9mufa0j41m@4ax.com>
On Fri, 12 Jul 2002 10:12:32 -0400, "TinCanMan" <Tin### [at] hotmailcom>
wrote:
> This is a bit difficult to explain but:  I want to be able to translate an
> object according to the turbulence value at its location.  Let's say we have
> a plane with a checker pattern on it and we place a little ball at the
> origin.  If we apply turbulence to the checker pattern, the point that was
> originally at <0,0,0> is now somewhere else defined by the turbulence
> parameters.  I would like to be able to move the sphere to this new
> location, something along the lines of:

Can you use user defined functions to recreate turbulence behaviour ?
If yes, that's could be solution (using some noise functions additionaly).

ABX


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From: Christoph Hormann
Subject: Re: Translate by turbulence
Date: 12 Jul 2002 10:22:46
Message: <3D2EE636.107D3BD6@gmx.de>
TinCanMan wrote:
> 
> [...]
> Does anyone have any idea on how this can be done in 3.5?

Have a look at the 'vturbulence()' function.

Christoph

-- 
POV-Ray tutorials, IsoWood include,                 
TransSkin and more: http://www.tu-bs.de/~y0013390/  
Last updated 30 Jun. 2002 _____./\/^>_*_<^\/\.______


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From: TinCanMan
Subject: Re: Translate by turbulence
Date: 12 Jul 2002 10:23:32
Message: <3d2ee664$1@news.povray.org>
>
> Can you use user defined functions to recreate turbulence behaviour ?
> If yes, that's could be solution (using some noise functions additionaly).
>

Possibly.
How would you get the translation value from the noise function?

-tgq


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From:
Subject: Re: Translate by turbulence
Date: 12 Jul 2002 10:35:50
Message: <q5qtiucq5q9a7dnt2pthadd6g9sbk4r7t3@4ax.com>
On Fri, 12 Jul 2002 16:22:46 +0200, Christoph Hormann <chr### [at] gmxde>
wrote:
> > Does anyone have any idea on how this can be done in 3.5?
>
> Have a look at the 'vturbulence()' function.

It can be wrong solution when you want displace geometry instead of vector as
for displacement in isosurfaces.

ABX


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From: TinCanMan
Subject: Re: Translate by turbulence
Date: 12 Jul 2002 10:36:37
Message: <3d2ee975$1@news.povray.org>
>
> Have a look at the 'vturbulence()' function.
>
> Christoph
>

Thanks, but it appears to be the opposite of what I want (if I understand
turbulence properly).  The vector returned by vturbulence() for pt A is the
original vector of the point that is essentially now located at A rather
than where the point that was originally at A is now.

-tgq


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From:
Subject: Re: Translate by turbulence
Date: 12 Jul 2002 10:37:50
Message: <i8qtiusukna1bkaftjqee1nekhildarvqe@4ax.com>
On Fri, 12 Jul 2002 10:23:11 -0400, "TinCanMan" <Tin### [at] hotmailcom>
wrote:
> > Can you use user defined functions to recreate turbulence behaviour ?
> > If yes, that's could be solution (using some noise functions additionaly).
>
> Possibly.
> How would you get the translation value from the noise function?

<f_noise(x,y,z),f_noise(y,z,x),f_noise(y,z,x)> ?

ABX


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From: TinCanMan
Subject: Re: Translate by turbulence
Date: 12 Jul 2002 10:40:34
Message: <3d2eea62$1@news.povray.org>

news:i8qtiusukna1bkaftjqee1nekhildarvqe@4ax.com...
> On Fri, 12 Jul 2002 10:23:11 -0400, "TinCanMan"
<Tin### [at] hotmailcom>
> wrote:
> > > Can you use user defined functions to recreate turbulence behaviour ?
> > > If yes, that's could be solution (using some noise functions
additionaly).
> >
> > Possibly.
> > How would you get the translation value from the noise function?
>
> <f_noise(x,y,z),f_noise(y,z,x),f_noise(y,z,x)> ?
>
> ABX

Hmm, I'll try this out.

After reading more into how turbulence works I don't think there is a simple
solution to this.  Turbulence works by grabbing a value *from* the
turbulated location rather than moving the point *to* a turbulated location.

-tgq


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From:
Subject: Re: Translate by turbulence
Date: 12 Jul 2002 10:43:47
Message: <ejqtiu85qkheglkr0pucrpsj3p4jdvi3gd@4ax.com>
On Fri, 12 Jul 2002 10:36:16 -0400, "TinCanMan" <Tin### [at] hotmailcom>
wrote:
>
> Thanks, but it appears to be the opposite of what I want (if I understand
> turbulence properly).  The vector returned by vturbulence() for pt A is the
> original vector of the point that is essentially now located at A rather
> than where the point that was originally at A is now.

I'm affraid it will be the same in my solution. What you are looking for is
bidirectional (reversable) turbulence (noise). I have looked for this kind if
noise at the time when I was working on deform patch. I passed but perhaps you
will find it.

ABX


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From: Christoph Hormann
Subject: Re: Translate by turbulence
Date: 12 Jul 2002 10:50:11
Message: <3D2EECA2.BFD1426@gmx.de>

> 
> It can be wrong solution when you want displace geometry instead of vector as
> for displacement in isosurfaces.

I think TinCanMan only wanted to translate a sphere.

Christoph

-- 
POV-Ray tutorials, IsoWood include,                 
TransSkin and more: http://www.tu-bs.de/~y0013390/  
Last updated 30 Jun. 2002 _____./\/^>_*_<^\/\.______


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