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This actually gives rather shitty results for power 8 mandelbulb sampled at ~128x128x128 resolution (edit: turned out to be mainly due to lack of bits per voxel - see below) Same after extracting isosurface with over 300K polygons to blender:



I don't see how increasing resolution could help, but will try, just to be sure.

My own rendering experiments were based on volume data as well. All the "high definition" imagery I presented on these forums used sampling grids of at least 1000^3 voxels. Simply speaking, the voxels need to be roughly as small as the pixels of a 2d rendering.

Volume rendering fractals is a brute force approach, but it has the advantage of being very general. There is nothing that cannot be rendered. But it can be very difficult to get an accurate sampling of the volume in the first place.

if you want "smooth" surfaces, you have to deal with lower iterations .... but hey, it is a fractal, what did you expect when increasing resolution !?

the deeper you go the higher iterations you need, but for smooth look on the whole set, iteration count of 4 or 5 is enough!
 

I continue messing with it, log-log shading seem to give better results.

my feeling is that there is some subtle difference between "bumpy" and "absolute noise".

as this is volume data, you could also try to make the density iteration-depth based. Higher iterations being more transparent.
This way, you'd get the basic shape pretty clear but the increasing level of fuzzyness will be weakened.
If I remember correctly, bib used soimething similar on some of his renders of the Mbulb....

ok, so I would consider smoothness problem solved for isosurfaces. it persists, however, in volume rendering mode. why do I care? well, I was thinking about displaying several isosurfaces at the same time with some nice transparent shading but, even if you can do that by importing those in blender once, or twice, this is a problem when you need 100s of frames.

and here comes volume rendering feature: they have this transfer function that essentially maps your voxel value to color/opacity. so I thought, if you leave everything transparent, and make some interval a...b slightly opaque, you would have nice colored shell in result. this is indeed true for outer shells (blue in the video below), but inner shells (yellow) are ripped into filaments, and innermost shells (not present) are dispersed in random dots that look like noise (this eventually happens to isosurfaces too, but they are able to resist rupture much longer).

<a href="http://www.youtube.com/v/nIx9AA8BDfg&rel=1&fs=1&hd=1" target="_blank">http://www.youtube.com/v/nIx9AA8BDfg&rel=1&fs=1&hd=1</a>

obvious way to solve this would be to increase data resolution up to few GBs, but that defeats the purpose, because then it would be actually faster to raytrace the fractal over at every frame (which also does not have rupture problem and gives any resolution you want). another obvious solution is to use bigger a...b interval, but I personally find think shells just result in ugly blurry dirty large unnecessary spot. so the only option left is to make smooth voxel values gradient even smoother.

I am currently using log-log method basically, and looking for ideas to modify it so that it would produce results similar to flood-fill near the set, gradually fading into normal shading at the distance: