One of the things that has always been annoying about playing a video game, especially roleplaying games, is the static setting. Buildings, vehicles, and characters don’t do anything more than exist to serve the player. They don’t create a real, virtual world; they create the illusion of one. Players discover quickly that game worlds are static and lack depth, and that destroys immersion.
Morrowind, the predicessor to Oblivion, was no different than any other roleplaying game in this regard. You could count on the non-player characters to be at certain places all the time, never sleeping or visiting a friend or plowing a field or sleeping. They just stood in their specified location, perhaps wandering a few feet here or there, and wait for the player to engage them when it comes time for their part in the story.
Fortunately, things have changed.
Oblivion sports a new Artificial Intelligence system called the Radiant AI engine. It is a breakthrough in game technology. The Oblivion Wiki describes it:
Radiant AI works by giving NPCs a list of goals (only quests and interaction with the player character are scripted). They must decide how to achieve these goals by themselves based on their individual statistics. A hungry NPC might compare his current gold against his moral values to decide whether he will walk to a store and purchase food, or just steal it; a skilled archer can choose to hunt his own deer.
This system has improved the immersion of the game substantially. For instance, I was on a quest that involved breaking into the captain of the guard’s chambers to find some incriminating evidence. Upon entering the guard house I discovered the soldiers in the middle of a shift change. When a guard entered through the front door he would be greeted by a fellow soldier who would then inform him he was being replaced. The guard coming off-duty would then sit down at a large table and start to eat. This process continued for several minutes, one guard after the next, until the entire township’s guards had swapped places, dayshift to nightshift. My character, itching to complete his mission, was forced to sit at a bench nearby waiting for the off duty guards to finish eating and go to sleep.
The whole experience really made the game world come alive. I no longer feel like the game world exists to serve me, but that my character is simply one small being in a larger domain. The guard house experience changed my expecations. Instead of the NPC’s existing explicitly to serve me and my purpose, I was having to adjust my schedule and expectations around their actions. That doesn’t happen in video games, and when it does it is largely the result of pre-planned scripts written by the developers. Here, though, I just happened to walk into the guard house at exactly the right time of day to witness the shift change.
I’m not sure that the value of the Radiant AI engine can be described adequately, or determined in terms of money and sales. This is a serious improvement to video game design. Much like how Oblivion’s graphics have raised the bar for future games, so has the Radiant AI engine. Players are not going to accept static game worlds after playing Oblivion.
And why should they? This is an absolutely wonderful world to play in.