It is all in implementation and execution. I hope these can help you in the pursuit of what you need. However i found this one link that might be useful..
Field3D - an open source library for storing voxel data. It provides C++ classes that handle storage in memory, as well as a file format based on HDF5 that allows the C++ objects to easily be written to and read from disk.
(also)
Minetest - open source game very similiar to Minecraft
Voxel Article - graphical explanation of what a voxel is.
