Parametric UFO

Yesterday I found the railroader UFO http://www.thingiverse.com/thing:6283 but I couldn't generate the adequate gcode for printing. I tried to make one using OpenSCAD and this is the result :)

You can download the OpenSCAD file and improve it yourself. The module has one argument: size, which indicates how big is the ufo. I thing the belt can be improved! Feel fre to make your derivative.