How long does it take to compile a game of that magnitude?
Doing a full rebuild of all the libraries and gamecode itself for just one target (i.e. debug, release, or shipping) takes somewhere around an hour to complete.
Normally, you'd think we don't do much full rebuilds, but you'd be surprised at how much is still tweaked and improved at the base levels. Add to that all the data that needs to be preprocessed for size and speed improvements, and you can imagine how we love to honor that little comic sometimes
By the way, if it weren't for those rebuilds and data preprocessings, you wouldn't get much updates from Lar, I think. So I guess it's all for the Greater Good
