Far Cry 4's AI is So Clever Even Its Developers Can't Outwit It

By Nick Cowen on at

“The first thing it did was grab a vehicle," Dan Hay, Far Cry 4’s gravelly throated producer, tells us with genuine surprise. "It then tried to run the tester over. Repeatedly. We didn’t know the game could do that."

As gaming's open worlds become more complex, as does the artificial intelligence that powers our experiences within them. But as we found at a Ubisoft Montreal studio visit, it seems that even development teams can be bamboozled.

Far Cry 4's dev halcyon moment came when one of the quality assurance testers was chasing the game's chief antagonist, Pagan Min. Instead of writing the AI as a set piece of code that would act with a defined amount of responses, at this stage the developers had allowed it to have free reign.

“Pagan Min: do what you want to do,” laughs Hay. “So Pagan Min got in a truck and the tester got in a 'copter. The tester rained grenades down on the truck and took it out of action. So we thought, 'That’s game over for Pagan Min!' But that’s not what happened at all.”

Instead, Hay says the AI baddie leapt out of the truck and ran to the nearest friendly base. Once there, it called in a tonne of reinforcements and then took control of a mortar, blasting the tester's character out of the sky. The tester parachuted down to safety and found that they were in the middle of a pre-planned battle, surrounded by AI enemies.

The tester was able to take out a few of them, but the scripted skirmish wasn’t as easy as it had been on previous plays as the Pagan Min AI was now a new variable in the battle. Instead of a straight run-and-gun affair, there was a wildcard to keep an eye on in the firefight.

"So we leaned into that a lot more and tried to make the AI responsive to the player," says Hay. "Now it looks for opportunities to attack, we want to make it see the same opportunities that the player sees and respond in a similar fashion. The world is systemic. When you hit the world, the world hits back – hard."

This "learn, adapt and attack" approach appears prevalent throughout the game. The untamed, snow-capped Himalayan region of Kyrat – a fictional mish-mash of Nepalese, Thai and Tibetan cultures – and its AI appears to size up challenges and respond with equal force. On the surface, it looks and plays much like Far Cry 3, as expected, but this time it seems to genuinely hate you.

Sure, there's a narrative here, too, of a native returning home after years abroad in the West to scatter his recently deceased mother’s ashes before getting caught up with a civil war and a flamboyant, bleach-blonde psycho in a purple suit (that'll be Pagan Min).

But frankly, who gives a toss? This is a Far Cry game and, as anyone with any experience of the series knows, the real fun is to be had by going completely off-script.

In Kyrat that can mean ramming a rhino with an SUV, diving off the shores and swimming with school of fishes, or firing a rocket-propelled grenade launcher at a honey badger. Seriously, the last one is advisable, those things are vicious, deadly, quick and – most importantly – tough to draw a bead on.

See, there’s a delicate balance to the wilds of Kyrat; mess with nature here and she's not just likely to take it personally, she’ll mess with you right back. Ubisoft Montreal want players to have a good time, but they're not making this no cakewalk. The land of Kyrat feels like a living, breathing eco-system that doesn’t take kindly to nimrods stepping on its toes.

So if you fancy losing the plot and going full Cannibal Holocaust, when skinning a giant tortoise we recommended that you toss a slab of plastic explosive on to its shell and then detonate from a safe distance. If you don't, and the wind picks up, you're likely to end up flame-grilled to perfection.

 Far Cry 4 is out November 18 on PC, PS4, Xbox One, PS3, Xbox 360