Houdini vex Fractals

[originally posted on May 1, 2017]
a little compilation of experiments and tests with houdini volume procedural shader
there are:
basic mandelbrots
3d mandelbulbs with random julia sets ( 2-complex pow formula from wikipedia) https://en.wikipedia.org/wiki/Mandelbulb
mandelbox formula i googled somewhere on fractal forums and wikipedia https://en.wikipedia.org/wiki/Mandelbox
4d fractal is based on classic quaternions algebra
coloration logic is made up on the go

render times vary from 10-15 min per frame on 3d fractals to 40-80 min per frame on hard divings, that's why there are not too much of them, and some are in lower resolution

link to the paper for double precision emulation with floats: http://www.andrewthall.org/papers/df6...
actual vex include files are here: https://drive.google.com/file/d/0B0aB...
fractal hips are pretty messy, unfortunately, so i'll be cleaning up and posting here some files as time goes.

shattering fractals hip: https://drive.google.com/file/d/0B0aB... . I cleaned it up and left some notes and vex comments on how what stuff works.
And here are the dirty files. oh, really messy and dirty, you can follow the logic of cleanedup file(s) to navigate though the nightmares of these scenes: https://drive.google.com/file/d/0B0aB...