The blog talks about the technical wizardry behind the new lighting system, as well as the decisions that went into creating the system itself. "The new lighting system had to be designed within several constraints. First, the new lighting system couldn't require much artist time, because ArtCo was busy with other expansion work. Second, the new system couldn't be much more resource-intensive than the old lighting system. Third, the new system couldn't add huge amounts of data to the game's size," the blog says.
Check out the full article on the official website.