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From: Thomas de Groot
Subject: ripple/wave centers
Date: 10 Jan 2012 04:28:03
Message: <4f0c04a3$1@news.povray.org>
... are lying on a rectangular grid. Is it possible to randomly move 
those centers? I tried with warp but then only the patterns are warped 
but the centers remain at the same place.

Thanks!

Thomas


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From: Alain
Subject: Re: ripple/wave centers
Date: 11 Jan 2012 21:22:50
Message: <4f0e43fa@news.povray.org>

> ... are lying on a rectangular grid. Is it possible to randomly move
> those centers? I tried with warp but then only the patterns are warped
> but the centers remain at the same place.
>
> Thanks!
>
> Thomas
In fact, the centers are within a 1 unit box.

You can move them apart by scaling. In this case, you should also use 
frequency of the same value as the scaling if you want to keep the 
ridges separation unchanged.
There is nothing preventing you from applying some un-even scaling.
You can rotate the pattern any way you want.

You can try changing the noise generator to see if it have an impact.

The option of using some random stream could be interesting, but will 
probably need a more or less complete rewrite of the code for that pattern.


Alain


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From: Thomas de Groot
Subject: Re: ripple/wave centers
Date: 12 Jan 2012 02:53:40
Message: <4f0e9184$1@news.povray.org>
On 12-1-2012 3:22, Alain wrote:
> In fact, the centers are within a 1 unit box.
>
> You can move them apart by scaling. In this case, you should also use
> frequency of the same value as the scaling if you want to keep the
> ridges separation unchanged.
> There is nothing preventing you from applying some un-even scaling.
> You can rotate the pattern any way you want.
>
> You can try changing the noise generator to see if it have an impact.
>
> The option of using some random stream could be interesting, but will
> probably need a more or less complete rewrite of the code for that pattern.
>

Hmmm... ok. So a random placement of centers (within the unit box) is 
not possible; think for instance of rain drops on water. For the time 
being I probably can get away with un-even scaling for my project, 
although that shall deform the pattern I guess. Maybe an average of 
different randomly translated patterns would do the trick? I shall try.

Thomas


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From: Thomas de Groot
Subject: Re: ripple/wave centers
Date: 12 Jan 2012 04:29:58
Message: <4f0ea816$1@news.povray.org>
On 12-1-2012 8:53, Thomas de Groot wrote:
> [...]Maybe an average of
> different randomly translated patterns would do the trick? I shall try.
>

Yes, this work to satisfaction indeed and gives randomly spread centers. 
Best seems to use number_of_waves 1 and a low frequency.

Thanks for thinking aloud with me ;-)

Thomas


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