The story of Battlefield 2’s tumbling ball of murderous medics

Defib

Tom Francis is a former PC Gamer writer and current game developer who offered to give us his thoughts on some of the GDC sessions he's attending this year. You can follow the development of Tom's next game, Heat Signature, at its official site.">

My two favourite topics for talks by developers are AI and failure, so Tuesday’s GDC talk entitled ‘AI Disaster Stories’ was irresistible. The best story came from Tobias Karlsson, currently a software engineer at Microsoft, but who previously worked at DICE programming the bot AI for Battlefield 2.

Like many Battlefields that followed it, BF2 has a medic class who can bring back the dead. If you’re in the ‘man down’ state, but haven’t yet respawned, any medic can whip out their defibrillators, jolt your body, and bring you back to life—saving you a trip, and your team a point.

When Karlsson was tasked with putting together a presentation to show off the AI he was working on for Battlefield’s bots, demonstrating that they could play as a Medic and intelligently save lives seemed like a great example of their abilities. To show that this worked, he spawned one bot to be the victim, and another to be the medic. And since Battlefield 2 can handle lots of bots, he thought he’d show off by spawning a bunch more for good measure—about 10 in total. It’s an empty level, and they’re all on the same team, so everyone just stood around staring into space.

Then, he shot one of them in the head. Friendly fire was on by default in those days, so this kills the medic. All ten surviving medics snap to attention, staring intently at the victim, and all start running towards him. “And as they get closer,” Karlsson says, “This might be a good time to talk about how the defibrillator works.”

Before anyone had actually revived it, the body was completely surrounded by medics.

“The defibrillator is actually implemented as a very slow firing weapon.” You press fire to use it, your character yells “Stand clear!”, the defibrillator charges up, and then finally fires. It actually shoots out an invisible projectile a short distance ahead of you, and if that hits a downed colleague, they’re instantly revived. And if it hits someone who isn’t downed—usually an enemy—it stops their heart instead of restarting it.

The first medic reached the body, yelled ‘Stand clear!’ and charged his defibrillator. But before he’d even finished the word ‘Stand’, the next medics were yelling the same. Before anyone had actually revived it, the body was completely surrounded by medics, to the point that the others couldn’t even get to him.

The first medic’s defibrillator jolted the victim to life. He promptly stood up and was immediately taken out by the next medic’s defibrillator. “But fear not,” Karlsson says, “we have plenty of medics on hand.”

The victim was immediately revived. And immediately killed. And immediately revived. In fact, the only thing that changed at all was that, since they were all on a slight slope, the body slid a short distance down it each time the ragdoll collapsed. Since all the living medics clustered around it as it moved, Karlsson’s demonstration of the bot’s brilliant AI had become “a huge ball of medics rolling down a hill yelling ‘Stand clear!’”

Latest in FPS
Fragpunk FPS
Fragpunk review
Rainbow Six Siege year 9 season 2 key art - two Rainbow Six Siege operators facing each other
'Siege 2 was never on the table': Rainbow Six Siege X director explains why the 10-year-old FPS doesn't need a sequel
rainbow six siege sledge
After holding out for 10 years, Rainbow Six Siege is finally going free-to-play (kind of)
rainbow six siege x dual front mode
Rainbow Six Siege is getting its first permanent mode in 10 years, and it throws every Siege rule out the window
Fragpunk characters with weapon drawn
The latest big game on Steam is Fragpunk, or as I like to call it, 'kitchen-sink Counter-Strike'
spectre divide
Spectre Divide and its studio are shutting down after just six months: 'The industry is in a tough spot right now'
Latest in Features
Monster Hunter Wilds' stockpile master studying a manifest
Monster Hunter Wilds' new gyro controls are a fantastic option for disabled and able-bodied players alike
A busy marketplace in The Bazaar.
The Bazaar could be the future of autobattlers, if it stops strangling itself to death with its own microtransactions
Marvel Rivals characters - Hulk with his hands out as if he's grabbing the camera.
Marvel Rivals' growing roster of heroes scares me, but the game's director seems sure that all is under control: 'Everything is progressing smoothly'
Rainbow Six Siege year 9 season 2 key art - two Rainbow Six Siege operators facing each other
'Siege 2 was never on the table': Rainbow Six Siege X director explains why the 10-year-old FPS doesn't need a sequel
Gallica and the protagonist from Metaphor: ReFantazio.
The best deals in the 2025 Steam Spring Sale
Hands pushing poker chips on a table
Winning $2.6 billion in this poker videogame has completely ruined fake poker for me