"When building a voxel game, it is important to choose a data structure for representing the world early on.  This decision more than any other has the greatest impact on the overall performance, flexibility, and scale of the game.  This post discusses some of the possible choices that can be made along these lines, and hopefully give a better explanation of what sort of technical considerations are involved.  In fact, I posit that some commonly held performance assumptions about Minecraft-type engines are probably wrong." - Amit Patel from Bookmarklet