Virtox's Julia Vase series is one of my favorite things in the whole wide Thingiverse. He never published his workflow so I set out to reverse engineer my own version. After all, how hard could it be to voxel stack a non-linear perturbation of a Julia set? It is actually quite easy and I posted a video at https://www.youtube.com/watch?v=8VmPtCf8m34 so anyone can explore these amazing forms. If you try it be sure to post what you come up with and comment any problems you have and any improvements you make to the technique.
The stl is a solid. To print it as a hollow vase just slice without a top or infill. This usually works better than a baked in wall thickness.
We talked about this on the 3D Printing Today podcast available on iTunes, Stitcher radio or direct from the source at http://threedprintingtoday.libsyn.com/