Former Sims 4 developer: sims don't plan ahead by design

At their core, sims meet their needs one moment at a time rather than thinking through a sequence of actions, David "Rez" Graham says. Graham, who served as lead AI programmer for the original release of The Sims 4 over a decade ago and is now director of game programming at the Academy of Art University, always wanted sims to take a more thoughtful approach when left to their own devices.

Current sims run AI on a cadence and pick the next objective based on motives and traits, so they can’t autonomously decide to go to bed early to exercise before work, for example. A player can queue sensible tasks, but a sim will often stay up playing video games until 2 a.m.

Graham and the lead AI programmer on The Sims 3 both tried adding planning to the simulation, he said, but the idea was repeatedly shot down because planned behavior needs to be clearly telegraphed to players. He gave the example of someone riding an escalator up and then immediately back down; without a visible reaction, players assume it’s a bug.

sims 4, sims 3, david graham, game ai, ai programming, planning, autonomy, task queue, motives, traits