Nope - good guess though. :) Funny story about marching cubes: in 2004, when I was creating my first major game engine, I "invented" the marching cubes algorithm without knowing that it already existed (and at that time, was patented) - a testament to how stubborn I am about learning on my own.

I am actually using ray-cast volumes, rendered to a hexagon (6 tris). Each vertex in the hexagon contains two points, a front and back location of the equivalent cube. (If you look a a cube in isometric perspective, it looks just like a hexagon which is why I used this technique -- another thing I'm sure that has been done before me). :) Another optimization over a standard cube is that a cube contains 12 triangles, and would have double redundancy on fill time.