I want to compute a 3D Julia fractal with quaternions that can be rotated. So, if I have a cuboid, I can say for every point, it contains to the fractal or not. These are volumetric informations. But for the display, I need only the surface. So, how can I convert the volumetric data to surface informations consisting of triangles or quads? Do you know an algorithm or strategy for that?
If you have volumetric data (you can calculate a floating point value at any point in 3D space), then you can convert that to geometry using either the marching cubes or marching tetrahedrons algorithms. There's a jME implementation of marching tetrahedrons at this wiki article: http://www.jmonkeyengine.com/wiki/doku.php?id=rendering_scalar_fields#polygonisation
Please let me know if the classes in the wiki are usable, and if you found any improvements. And we want to see some screenies please, fractals are cool