POV-Ray : Newsgroups : povray.general : turbulence and size Server Time
10 Aug 2024 05:17:20 EDT (-0400)
  turbulence and size (Message 1 to 2 of 2)  
From: ingo
Subject: turbulence and size
Date: 13 Mar 2000 14:34:20
Message: <8EF6DF74Dseed7@204.213.191.228>
If I have a pigment{boxed}, it is contined by a box{-1,1}.

Now if I add a turbulence to the pigment, pigment{boxed turbulence 0.2}
is the minimal box of witch I can be sure it contain the pigment 
box {-1.2,1.2} ?

Ingo

-- 
Photography: http://members.home.nl/ingoogni/
Pov-Ray    : http://members.home.nl/seed7/


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From: Josh English
Subject: Re: turbulence and size
Date: 13 Mar 2000 15:31:41
Message: <38CD4FF2.D4C5B88F@spiritone.com>
Well, it depends.
The following is complete conjecture on my part. Please correct me if I'm
wrong.
The octaves value is the number of "steps" the turbulence calculation
takes, and the omega value is the ratio of any step to the previous ones.
The default values are 6 and 0.5. I believe the length of the first step is
equal to the turbulence value specified.
To find the maximum distance, assume all movement is along the x axis and
in a straight line.
So if you declare turbulence 0.2, and the edge of the original pattern is
at x=1, then the first step is at 1.2, the second step is at 1.3, the third
step is at 1.35, the fourth step is at 1.375, and the fifht step is at
1.3875, and the sixth step is at 1.39375 units along the x axis

So the maximum box would be {-1.39375,1.39375}
If anyone knows the real method used, please let me know

Josh



ingo wrote:

> If I have a pigment{boxed}, it is contined by a box{-1,1}.
>
> Now if I add a turbulence to the pigment, pigment{boxed turbulence 0.2}
> is the minimal box of witch I can be sure it contain the pigment
> box {-1.2,1.2} ?
>
> Ingo
>
> --
> Photography: http://members.home.nl/ingoogni/
> Pov-Ray    : http://members.home.nl/seed7/

--
Josh English
eng### [at] spiritonecom
"May your hopes, dreams, and plans not be destroyed by a few zeros."


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