This puzzle is a shape modification of a Rubiks cube. This file includes masters only; you will have to mold and cast the rest yourself.
See http://twistypuzzles.com/forum/viewtopic.php?f=15&t=15148 for more information.
The parts are hollow by default. I do not recommend casting them hollow. Each set of masters comes with caps that are labeled "C" for corner cap and "E" for edge cap. Insert the caps and mold the parts as usual and you will get solid parts from hollow masters. The puzzle accepts standard DIY Type A hardware and cores.