what do you mean by go from night to day?
dark ai allows you to assign ai to object in your game world. things like "go here" or "patrol there", avoid this, attack that your friends with these guys, etc. anything more deep needs to be simulated using the available commands.
if you want different behavior for day and night, i would make a day and a night subroutine for contolling your characters.
then I would make a counter to tell the time, then select the relevant subroutine.
if its more of a general day night thing I would consider using dark clouds, It has a pretty good day/night thing going on.
Sometimes I like to use words out of contents
