The first 'technical challenge' - The Lichtenberg-figure, The winners are?

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Offline Caleidoscope

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« on: June 28, 2020, 11:53:46 AM »
We have 2 contest, general fractal and a Theme fractal contest. Both more judged  for art/look than math as. So we thought it to be a nice idea to have a big challenge once in a while that will go deeper.  Also more open for other forms, such as craftmanship (woodburning for example), drawing, video, even audio or poetry. Whatever you like as long as it is within the  the requirements for the challenge.

The first challenge is is an idea from CoryMcG (read more about it in the discussion on : https://fractalforums.org/fractal-image-of-the-month/70/fractal-image-of-the-month-discussion-thread/150 ) :
My suggestion for a first challenge is Lichtenburg Figures. I'll attach an image from Wikipedia.
(the file is credited to Bert Hickman of http://www.capturedlightning.com/ )
These are paths often carved out by high-voltage electricity in specific circumstances.
Such figures can be made using particle simulation, I know, but since this is only as complex as the size of the particles used, I'd argue that that method would not be fractally enough, and encourage other solutions.
These are my thoughts on this for now. I think this could be fun, and I hope everyone else likes these ideas too.

RULES:
This topic will open at  01-07-2020  and will be open to participate until 27-08-2020 midnight Amsterdam time.  The voting period will be till the end of 14-9-2020, midnight Amsterdam time.  The winners will be announced after that. 

To participate, just post in this thread and attach the image or file to your post. (don't use the gallery) Please give it a good name, and add interesting info, like software/formula used, parameter sharing is very welcome, or pictures how you made it etc. For images use a good resolution, but remember the max. size allowed. 3840x3840  Max  filesize: 5.01MB

For any question or suggestion or critics, please use the discussion thread. Any remark put here during the challenge, will be removed.
To keep the challenge clear from noise.

Ok, we hope you will have fun with this rather unique challenge, dazzle us all with your creativity.   :thumbs:  :yes:
I can't wait!   :thumbs_up_by_craig_m:




Linkback: https://fractalforums.org/fractal-image-of-the-month/70/the-first-technical-challenge-the-lichtenberg-figure-the-winners-are/3624/
« Last Edit: September 15, 2020, 12:03:19 AM by Caleidoscope »

Offline kohlenstoff

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« Reply #1 on: July 01, 2020, 06:52:16 PM »
Lichtenberg

I had already some nice tree flames. I just had to remove most of the symmetry simply by moving some transformations and the result looks quite realistic. On zoom you can see more and more details, just like you could see in the original figures in resin. This fractal has also an intentionally made slight DOF effect. This one looks like a lichtenberg figure made by impact on the side of a resin plate. Impact point of the trigger spike is close to the center.

I especially like this topic because im very interested in this phenomenon.

Made with Fractron9000
The original Flame

---------------------------
  <flame name="holographicx39Lichtenberg3" version="Fractron9000 0.4" size="800 600" center="-0,4723 -0,2356" scale="74,9998" zoom="0" rotate="0" background="0 0 0" brightness="1,952" gamma="2,588" vibrancy="0">
    <xform weight="1" color="1" f9k_color2="0,5" linear="1" sinusoidal="1" coefs="0,125 0 0 0,125 0,002 0" />
    <xform weight="1" color="0,25" f9k_color2="1" linear="1" sinusoidal="1" coefs="0,125 0 0 0,125 -0,002 0" />
    <xform weight="1" color="1" f9k_color2="0" linear="1" sinusoidal="1" coefs="0,125 0 0 0,125 0,0005 0" />
    <xform weight="1" color="0" f9k_color2="0,5" linear="1" sinusoidal="1" coefs="0,125 0 0 0,125 -0,0005 0" />
    <xform weight="1" color="1" f9k_color2="0,1732284" spherical="1" coefs="0,125 0 0 0,125 0,375 -0,625" />
    <xform weight="1" color="0" f9k_color2="0,1889764" spherical="1" coefs="0,125 0 0 0,125 -0,25 -0,5" />
    <xform weight="1" color="0,3307087" f9k_color2="0,7480315" spherical="1" coefs="0,125 0 0 0,125 0,125 0,75" />
    <xform weight="1" color="0,7637795" f9k_color2="0,8188977" spherical="1" coefs="0,125 0 0 0,125 0 0,5" />
    <xform weight="1" color="1" f9k_color2="0" spherical="1" coefs="0,125 0 0 0,125 0,375 -0,625" />
    <xform weight="1" color="0" f9k_color2="0" spherical="1" coefs="0,125 0 0 0,125 -0,25 -0,5" />
    <xform weight="1" color="0,35" f9k_color2="0,6" spherical="1" coefs="0,125 0 0 0,125 0,125 0,75" />
    <xform weight="1" color="0,75" f9k_color2="0,7" spherical="1" coefs="0,125 0 0 0,125 0 0,5" />
    <xform weight="1" color="1" f9k_color2="0,472441" linear="1" coefs="0,125 0 0 0,125 0,375 -0,625" />
    <xform weight="1" color="0" f9k_color2="0,496063" linear="1" coefs="0,125 0 0 0,125 -0,25 -0,5" />
    <xform weight="1" color="0,2440945" f9k_color2="1" linear="1" coefs="0,125 0 0 0,125 0,125 0,75" />
    <xform weight="1" color="0,511811" f9k_color2="1" linear="1" coefs="0,125 0 0 0,125 0 0,5" />
  </flame>

Offline pauldelbrot

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« Reply #2 on: July 01, 2020, 11:49:00 PM »
Mandelbrot, center coordinates -1.1477908048866525 + 0.2752899772141804i, modified DE and greyscale gradient used for coloring.
« Last Edit: July 02, 2020, 05:41:01 PM by pauldelbrot »

Offline 3DickUlus

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« Reply #3 on: July 04, 2020, 06:33:58 AM »
is this one :confused2:

« Last Edit: July 05, 2020, 11:47:09 PM by 3DickUlus »

Offline quaz0r

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« Reply #4 on: August 14, 2020, 01:58:55 PM »
im not sure how many people are confident in what qualifies or not.  im not really sure myself but i thought my current background pic is kinda in the ballpark maybe  :-X  specifically the negative space.

Offline claude

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« Reply #5 on: August 16, 2020, 02:31:25 AM »
Dielectric Breakdown Model as per
Quote
Fractal Dimension of Dielectric Breakdown
L. Niemeyer, L. Pietronero, and H. J. Wiesmann
Phys. Rev. Lett. 52, 1033 – Published 19 March 1984
It is shown that the simplest nontrivial stochastic model for dielectric breakdown naturally leads to fractal structures for the discharge pattern. Planar discharges are studied in detail and the results are compared with properly designed experiments.
DOI: https://doi.org/10.1103/PhysRevLett.52.1033

Code: [Select]
//  gcc -O3 -fopenmp -march=native -std=c99 -Wall -pedantic -Wextra dbm.c -lm
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define W 1920
#define H 1080
#define N 16
const float eta = 3;
unsigned char pgm[H][W];
float phi[2][H][W];

struct cell
{
  unsigned short j;
  unsigned short i;
  float probability;
};

int nboundary = 0;
struct cell boundary[H * W];

int main(int argc, char **argv)
{
  memset(pgm, 0, sizeof(pgm));
  pgm[H/2][W/2] = 255;
  for (int j = 0; j < H; ++j)
  {
    for (int i = 0; i < W; ++i)
    {
      phi[0][j][i] = 1;
      phi[1][j][i] = 1;
    }
  }
  for (int j = 0; j < H; ++j)
  {
    phi[0][j][0] = 0;
    phi[0][j][W-1] = 0;
    phi[1][j][0] = 0;
    phi[1][j][W-1] = 0;
  }
  for (int i = 0; i < W; ++i)
  {
    phi[0][0][i] = 0;
    phi[0][H-1][i] = 0;
    phi[1][0][i] = 0;
    phi[1][H-1][i] = 0;
  }
  int w = 0;
  nboundary = 4;
  boundary[0].j = H/2 - 1;
  boundary[0].i = W/2;
  boundary[1].j = H/2;
  boundary[1].i = W/2 - 1;
  boundary[2].j = H/2;
  boundary[2].i = W/2 + 1;
  boundary[3].j = H/2 + 1;
  boundary[3].i = W/2;
  for (int f = 0; f < W * H; ++ f)
  {
    // compute field with Laplace equation
    for (int n = 0; n < N; ++n)
    {
      double t = 0;
      #pragma omp parallel for collapse(2) reduction(max:t)
      for (int j = 1; j < H - 1; ++j)
      {
        for (int i = 1; i < W - 1; ++i)
        {
          if (pgm[j][i])
          {
            phi[!w][j][i] = 0;
          }
          else
          {
            phi[!w][j][i]
              =(phi[w][j-1][i]
              + phi[w][j][i-1]
              + phi[w][j][i+1]
              + phi[w][j+1][i]
               )/4;
          }
          double s = phi[!w][j][i];
          t = s > t ? s : t;
        }
      }
      w = !w;
      float s = 1.0f / t;
      #pragma omp parallel for collapse(2)
      for (int j = 1; j < H - 1; ++j)
      {
        for (int i = 1; i < W - 1; ++i)
        {
          phi[w][j][i] *= s;
        }
      }
    }
    // update boundary probabilities
    double t = 0;
    for (int n = 0; n < nboundary; ++n)
    {
      int j = boundary[n].j;
      int i = boundary[n].i;
      t += (boundary[n].probability = powf(fmaxf(0, phi[w][j][i]), eta));
    }
    t = 1.0f / t;
    for (int n = 0; n < nboundary; ++n)
    {
      boundary[n].probability *= t;
    }
    // pick weighted random boundary point
    int m = -1;
    while (m == -1)
    {
      double q = rand() / (double) RAND_MAX;
      t = 0;
      for (int n = 0; n < nboundary; ++n)
      {
        t += boundary[n].probability;
        if (q < t)
        {
          m = n;
          break;
        }
      }
    }
    // update shape
    pgm[boundary[m].j][boundary[m].i] = 255;
    int j = boundary[m].j;
    int i = boundary[m].i;
    for (int n = m + 1; n < nboundary; ++n)
    {
      boundary[n - 1] = boundary[n];
    }
    nboundary -= 1;
    int points[4][2] = { { j - 1, i }, { j, i - 1 }, { j, i + 1 }, { j + 1, i } };
    for (int k = 0; k < 4; ++k)
    {
      j = points[k][0];
      i = points[k][1];
      if (1 <= j && j < H - 1)
      {
        if (1 <= i && i < W - 1)
        {
          if (! pgm[j][i])
          {
            int present = 0;
            for (int n = 0; n < nboundary; ++n)
            {
              if (boundary[n].j == j && boundary[n].i == i)
              {
                present = 1;
                break;
              }
            }
            if (! present)
            {
              m = nboundary++;
              boundary[m].j = j;
              boundary[m].i = i;
            }
          }
        }
      }
    }
    // output frame
    if ((f % 1024) == 0)
    {
      fprintf(stdout, "P5\n%d %d\n255\n", W, H);
      fwrite(pgm, W * H, 1, stdout);
      fflush(stdout);
    }
  }
  return 0;
}

Output frames were numbered, a subselection of frames at powers of two (from 1, 2, 4, ..., 256) were Gaussian blurred in GNU IMP with radius 256, 128, 64, ..., 1.  The layers were combined with additive blending and exported to PNG.

Offline GBy

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« Reply #6 on: August 22, 2020, 10:19:37 AM »
Not specially 'that' technical
Anyhow I tried to render this location which features a few lightning-like patterns
(-1.35559074267287, 0.068410397524657)
« Last Edit: August 22, 2020, 11:49:23 AM by GBy, Reason: adjust zoom level »

Offline Caleidoscope

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« Reply #7 on: September 15, 2020, 12:00:15 AM »
Thank you all for participating and thank you voters.

The winners of the The first Technical challenge are:

Gold, first place:  Claude with:   'Dielectric Breakdown Model as per'    with 26  points.

Silver, third place: pauldelbrot with: 'Lichtenberg'  with  19   points.


Bronze,  third place:  quaz0r  with:  'the negative space.'   with 18  points.                             


Congratulations to you all!   :toast:

Offline pauldelbrot

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« Reply #8 on: September 15, 2020, 12:24:27 AM »
Thank you.

Offline claude

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« Reply #9 on: September 15, 2020, 02:33:20 PM »
Thanks all!

Offline Sabine62

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« Reply #10 on: September 15, 2020, 05:45:53 PM »
Congratulations all!  :clapping: :clapping: :clapping:

I highly enjoyed watching this contest and its interesting entries, thank you!  :yes: :thumbs:
To thine own self be true

Offline 3DickUlus

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« Reply #11 on: September 16, 2020, 06:03:10 AM »
Indeed, congrats to all  :clapping: ... and hats off to Claude  :worship:
I think "The first FractalForums Technical Challenge" went well  :horsie: