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-- Mike Condron

The summer hiatus is over and HPDZ is back to generating new and amazing fractal animations!

What's New

Secant Butterfly II Wins Third Place in Fractal Image Contest!

The results of the Fractal Forums annual 2D Image Contest are in, and HPDZ's own image Secant Butterfly II earned third place in this competition!


Project 17

Click here for the Project 17 page on HPDZ.NET.

About a year ago, William (FractalWizz on YouTube) suggested I make an animation based on one of my still images (the third from the left below). I thought it would be a good project to run through the summer. It finished initial rendering around Aug 8 and now has been colorized and encoded and given a very unimaginative name.



The video zooms into the cusp of the Mandelbrot set, a great place to find images with lots of spirals and complex patterns. I have avoided it for animations because of the "aliasing" problem discussed below. Animations from this area tend to have a huge amount of noise, and reducing that noise dramatically increases the time it takes to calculate the fractal data.

This animation is not very complicated in terms of its motion, just a zoom-in, a pause, and another shorter zoom-in. But it has two important technical features described below, for those who are interested.


Although the motion in this video is not very complex, it was still possible to mess it up. A short example of how something went very wrong with the scaling of the motion is on the web site's page for this project.



Just about every fractal animation has some visual noise in it, which sometimes is called "aliasing". This noise is due to the fractal having infinite detail, so sampling it digitally to make a video is similar to sampling random noise. The sparkling is usually not too annoying, but in the cusp region of the set, it gets very annoying indeed.

This is the first animation I've made that uses anti-aliasing. I've developed a good set of tools for anti-aliasing still images, and they work perfectly fine for videos too, but they increase the rendering time dramatically. Project 17 uses 9X oversampling, so it took 9 times longer to render than it would have taken with no anti-aliasing. There is still some sparkle noise, but it is far less than the original, unfiltered, version.

Software Improvements

Global Colorizing

A recurring theme in the animations on HPDZ.NET is exploring new ways to colorize the videos to achieve optimal use of the color palette. Project 17 uses a new and very simple, yet surprisingly effective, method. Details are on the website page for this video. Essentially, a histogram is generated using all fractal data values from all frames in the video, and that histogram is used to set the color mapping. It is something I have wanted to try for a long time, but it seemed too simple to work.

Finally, my curiosity drove me to spend an afternoon writing the code for this, and it works surprisingly well. There is a little flattening out of the coloring in the last few seconds of video, but that can probably be fixed, and the software for this method is very simple, so it is easy to experiment with new variations.


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