Hacker News new | comments | show | ask | jobs | submit login
True 3D Mandlebrot-type fractal (2007) (fractalforums.com)
53 points by pirocks 7 months ago | hide | past | web | favorite | 8 comments

This is the thread where early research into the Mandelbulb happened. It's historically interesting, but as the final post says: "This topic has been locked because the main thread theme has reached some kind of a result, and is simply far to big now"

For those who are more interested in the Mandelbulb in general than the history of its discovery, the Wikipedia page is a better starting point: https://en.wikipedia.org/wiki/Mandelbulb

You can apply the Mandelbrot iteration (or any similar scheme) to quaternions to get 4d fractals, and although they are 'true' 4d, it doesn't add anything interesting. As I recall from doing this in high school 20+ years ago, you just get the normal set swept around two of the axes, so no new information.

It could be different with other fractals, I guess it's time to try again now that computers are fast and I can actually program!

Quaternion julia sets look pretty neat.

Especially when animated by varying over time the 3D hyperplane on which the object is projected. POV-Ray, the venerable open-source raytracer, has had a 4D Julia primitive for ages and with current processors is a pretty good way to explore the Julia space.

But the 4D versions don't exhibit the sort of dizzying complexity you can endlessly zoom into like the original Mandelbrot/Julia set. This is mentioned by the starter of the thread.

Oh wow, POV-Ray was finally open-sourced. I remember playing around with it maybe 15 years ago now. The Internet Ray Tracing Competition[1] was still a going concern, and one of the rules was that post-processing was disallowed. So people got motion blur by recompiling the program to average several frames together, which didn't count as post-processing since it was still a ray-tracer that did it.

[1] https://en.wikipedia.org/wiki/Internet_Ray_Tracing_Competiti...

Wasn't the source "always" available but just under a custom non-FOSS compatible license? I used to use POV-Ray quite a bit and participated in the IRTC a few times as well. Even 15 years ago the reason for keeping the legacy license was IIRC mostly that it would have been a huge task to get in touch with all the contributors or alternatively to rewrite all the parts that could not have been relicensed.

Yeah the source was available for as long as I used it (hence people being able to hack on it for the motion blur), but always under the no-redistribution license. I wasn't yet very familiar with FOSS but I remember understanding that the source being available was a big deal, and the no-redistribution clause was also a big deal.

There is a program to visualize 3D Mandelbrot:


Applications are open for YC Summer 2018

Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact