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I first started playing with Mandelbulbs using Subblue's (Tom Beddard) Adobe Pixel Bender file mandelbulb.pbk (3D Mandelbulb Ray Tracer). Mostly because I was already using Photoshop and was familiar with Pixel Bender.

While playing I happened to come up with a shape very close to what I needed for some art I am working on. But I needed more versatile lighting and colouring. Plus being able to convert to a 3D mesh would be really useful as can be done using the Voxelstack option of Mandelbulb 3D. (image of object attached)

So I tried to duplicate my work from Subblue's program into Madelbulb 3D. So far I have not been able to do it. Partially it may be I am just not able to find the correct formula. Or I may need to write my own formula. Either way, I am hoping for some hints or help where to go to do this. Or if it is possible at all?

1) Has anyone else tried duplicating a Subblue mandelbulb.pbk object in Madelbulb 3D? Is there a formula already written?

I tried the "general" Mandelbulb 3D formula. With default parameters the "general" mandelbulb looks very close to the subblue image using its default parameters. But then I try a negative power as the subblue pbk allows. The results are completely different than what subblue's mandelbulb does.

2) Is there a formula which does a standard mandelbulb handling negative powers similar to subblue's?

For my shape using subblue's mandelbulb.pbk. I also need to restrict the y value as per the description for the "radiolaria" option:
radiolaria: when enabled this option constrains the y component of the triplex number resulting in interesting spiky structures.
(the formula restricts y to min:-4 and max:4)

3) Is there a formula which allows me to restrict the min/max values of the y component of the triplex number?

I am also attaching mandelbulb.pbk in case you need to look at the original code. I have converted it to a simple text file since .pbk is not an allowed file type for attachments in this forum.

Thank you,

- Timothy
- Timothy

Thank you KRAFTWERK,

Did you happen to save a "fixed" version of the mandelbulb.pbk file? If so, could you send it to me (attach to reply)? That way I could compare the two and reverse engineer Subblue's formula.

I know I will probably use Mandelbulb 3D from now on. However, in this case I just happened to come up with a shape which was close to perfect for a specific need. Trying to find a similar shape in the billions? trillions? infinite? possibilities in Mandelbulb 3D would be nearly impossible just by trying things randomly.

- Timothy

Never mind everyone. It seems I am on a useless quest. I finally found the forum post which indicates Mandelbulb 3D does not handle negative powers. Since what I was hoping to do required using negative powers, Mandelbulb 3D is not going to work for me 

Mb3d is the most flexible renderer ever, do not give up so soon

Indeed, i was also surprised about the shapes in the negative power bulb, thanks for pointing at it.

Unfortunately, and as you can see in the m3d images, there is an issue in coloring and normals when rendered inside and when the shape is iteration limited, like in this case.  But increasing max-iterations will slow down rendering even more.