POV-Ray : Newsgroups : povray.general : Transformations: Is there any random-wavy transformation? Server Time: 19 Jun 2019 07:27:50 GMT
  Transformations: Is there any random-wavy transformation? (Message 1 to 10 of 10)  
From: Sven Littkowski
Subject: Transformations: Is there any random-wavy transformation?
Date: 26 Feb 2018 05:54:07
Message: <5a93a0ff$1@news.povray.org>
Hi again,

after a looooong time (around 1 day) I am coming up with yet another
question:

Are there any transformations that can transform a flat tall thin box
into something wavy?

I decided to go this way (if it exists) because my other attempts to
create seaweed are not successful.

Ideally, the waves are stronger on one axis, but less on one or two of
the other axises. Random to some extend, but the strength of the
waveforms should be controllable.

Big thanks.

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From: Bald Eagle
Subject: Re: Transformations: Is there any random-wavy transformation?
Date: 26 Feb 2018 13:45:00
Message: <web.5a940f08693012a0c437ac910@news.povray.org>
http://www.f-lohmueller.de/pov_tut/addon/00_Basic_Templates/40_Isosurfaces_basic_functions/21_Isosurface_y_sine_concent
ric.txt


For your red algae, why not use some summed sine waves with different
frequencies to give an irregular waviness?


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From: Sven Littkowski
Subject: Re: Transformations: Is there any random-wavy transformation?
Date: 26 Feb 2018 14:19:59
Message: <5a94178f$1@news.povray.org>
Yes, sounds interesting, I would like to give a try!

But the URL is not functioning, can you check it? Thanks.

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From: Sven Littkowski
Subject: Re: Transformations: Is there any random-wavy transformation?
Date: 26 Feb 2018 14:21:10
Message: <5a9417d6$1@news.povray.org>
URL is now functioning, I copied entire string into browser address.

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From: Sven Littkowski
Subject: Re: Transformations: Is there any random-wavy transformation?
Date: 26 Feb 2018 14:54:45
Message: <5a941fb5$1@news.povray.org>
Okay, I just tried out that formula.

The problem is, only one surface is rippled, and the rippling is
concentric, like rings. And quite equal.

I, on the other hand, need to produce something that looks like a flag
in the wind: thin like a cloth, and irregular rippling (wave forms). I
am not even able (due to lack of understanding) to change the
mathematical formula in any beneficial way.


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Attachments:
Download 'sl - uwe-m. troppenz - grypania.png' (4 KB)

Preview of image 'sl - uwe-m. troppenz - grypania.png'
sl - uwe-m. troppenz - grypania.png


 

From: clipka
Subject: Re: Transformations: Is there any random-wavy transformation?
Date: 26 Feb 2018 15:53:40
Message: <5a942d84$1@news.povray.org>
Am 26.02.2018 um 14:43 schrieb Bald Eagle:

> For your red algae, why not use some summed sine waves with different
> frequencies to give an irregular waviness?

Drat, you beat me to it :)


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From: Bald Eagle
Subject: Re: Transformations: Is there any random-wavy transformation?
Date: 26 Feb 2018 15:55:01
Message: <web.5a942cc4693012a0c437ac910@news.povray.org>
Your formula is

y - cos(sqrt(x*x + z*z)*5*pi)*0.08

so y is varying as a function of x and z.

if you want the z to vary

try

x - (cos(sqrt(x*x + y*y)*5*pi)*0.08)/x

or something like that


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From: Bald Eagle
Subject: Re: Transformations: Is there any random-wavy transformation?
Date: 26 Feb 2018 16:20:00
Message: <web.5a9433a6693012a0c437ac910@news.povray.org>
clipka <ano### [at] anonymousorg> wrote:
> Am 26.02.2018 um 14:43 schrieb Bald Eagle:
>
> > For your red algae, why not use some summed sine waves with different
> > frequencies to give an irregular waviness?
>
> Drat, you beat me to it :)

Or - perturb a "linear spline" with Perlin noise.

Obviously the spline type would not be linear, but the starting points before
perturbation would be aligned linearly.

Or just use a loop, an array, whatever...


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From: Bald Eagle
Subject: Re: Transformations: Is there any random-wavy transformation?
Date: 26 Feb 2018 21:55:00
Message: <web.5a94815d693012a0c437ac910@news.povray.org>
#version 3.7;

global_settings {assumed_gamma 1.0}

#include "colors.inc"
#include "textures.inc"

camera {
 location <0, 5, -10>
 look_at  <0, 5, 0>
 right     x*image_width/image_height
 up y
}

light_source {<20, 50, -100> White shadowless}
light_source {<0, 5, -1> White shadowless}

#declare F = function {z - (cos(x*4*pi)*0.5)/x}

isosurface { // ------------------------------------------------------------
  function{
       abs(F (x, y, z))-0.1
   }
  threshold 0
  //accuracy 0.0000000001
  max_gradient 4
  contained_by {box {<0.01,-1.5,-1>, < 3.01, 1.5, 3>}}
  //open

  texture{ pigment{ color rgb<0.8,1,0.0>}
           finish { phong 1}
   }
  scale <1, 1, 1>
  rotate <80, 0, 0>
  translate < 0, 5, 0>
} // end of isosurface -----------------------------------------------------


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From: Sven Littkowski
Subject: Re: Transformations: Is there any random-wavy transformation?
Date: 27 Feb 2018 07:38:03
Message: <5a950adb$1@news.povray.org>
Yes, to some extend I could use this result.
But here is another problem: I have to admit, that I am not that good
with mathematical functions. What i mean is, that i would not know, how
to change this function to achieve what I need: something that resembles
a flag in the wind (just much narrower and longer, but the same thin).

I like, that the existing result of your example brings already some
waves, but they are very strong, still very straight between both
curves, and also too regular.

I admit, there is a really great spirit of helping with this group here.
At the same time I feel like I want to apologize to all of you, for
making so much trouble and keeping you all like working for me. I hope
you all accept my apology.

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