SurfBox - another cool Mandelbox variant

[DarkBeam]

I hand-drawn a strange function that I thought could be cool for experimenting with mutations of ABox.
The modification effect is neaty and deserves more deep looking.
Let me show you how it works, just a little tricky formula that adds a fold that will trigger after the normal folding limit to work like an abs() - so the result is something that stays on borderline between Amazing Surf and the old Box!

Code:

        // Mixed fold by Luca 2016.
        // do this for all 3d axis, or 4d axis if you have a 4d abox
        // Tglad normal fold is cfg->x = fabs(cfg->x + fold) - fabs(cfg->x - fold) - cfg->x;
	sg = sign(cfg->x);
	folder = sg * cfg->x- fold; // fold is Tglad's
	folder += fabs(folder);
	folder = min(folder, foldModX); // and Y,Z,W
	cfg->x -= sg*folder;

If foldMod = 0, you disable the fold of the corresponding axis. Nice to create curly surfaces aka amazing surf
Conversely if foldMod tends to infinity, you get Tglad's fold. I found that 2000 can be enough.
If foldMod = 2*fold, you get the perfect Mixed Folding, simulating abs() and fold at the same time.
If foldMod = 4*fold, you get a double folding just like doing fold twice.

Images on next post.

[DarkBeam]

The standard Amazing Box, but with modified folding with value 2. Strange features are already visible in MSet!

[DarkBeam]

Julia set of coords (0.3333333 ;0.3333333 ; 2) - a point on the critical square. A Julia of a normal ABox of that location looks like a solid cube, nothing else. Like the previous image, this is with all parameters as in the original first Tglad's Abox... minr=0.5 fold=1 scale = 2.
All the parts of this julia are infinitely thin, like Amazing Surfaces. But this formula also has solid parts making it really versatile ...

[KRAFTWERK]

Hmmmm, looks promising... Great idea Luca! 

[DarkBeam]

Thanks Johan, this formula hides many wonders

[mclarekin]

Looks fast  



I recognize that smooth spheric zone :0





http://www.fractalforums.com/index.php?action=gallery;sa=view;id=19328

[mclarekin]

@ DarkBeam

Can you remember if this fold looks like the yellow line on the chart.

So inside the fold limits - no change, then there is a transition , then an offset =  foldModX??

[DarkBeam]

Hello! No, my fold is conformal, no angle changes, only sign change in derivates. By the way, yes inside the folds nothing happens... Then Tglad fold (without changing the angle, so 1st angle sign inversion), then the derivate changes sign after a while, keeping continuity

[mclarekin]

Fortunately Buddhi always assures me there is no such thing as a stupid question, otherwise  :-.  If i had bothered to re-read the post instead of just copying the code and making some guesses I would have realized I was way off
 I assumed cfg was the abbreviation for "confusing" lol.

I will have another go and see what i get.

Cheers