FREE AI…you dumb sonova bitch!

While developing 50 Cent: Bulletproof I learnt a lot about the future of NPC’s within an action game. I know what you’re thinking; Bulletproof was linear?..Yes!……but its AI wasn’t.  

Partway through development, a hard choice was made to “tone down” the movement abilities of the NPCs. This was due to the amount of time we had remaining to finish the game; we wouldn’t have time to polish and debug everything the NPC’s could do. It was a smart move because time was against us, but, if you’d have seen what the AI’s were doing at that time…you’d know why I want to expand on their possibilities.   

Total script driven games cannot continue in larger worlds. Yes, it’s nice to have the occasional scripted event that gives that WOW factor, but, what would it be like to have that WOW moment at any time…anywhere…all the time or infrequent? Organic WOW moments? You do get small flashes of these occasionally in some of the bigger, sprawling games, they call it “emergent gameplay”…but we need to take it further with action games…much further.   

Just after Bulletproof, I began writing down ideas about where we could go with elements we touched upon (AI wise) in the last game. After discussing a lot of issues our with Petar (our AI guy), it was obvious that we should give more control to the GAME, rather than the designer. What I mean by that is; give AI’s more options of interaction in the environment AND drastically expand their animations (to facilitate the interactive elements). Allow them more freedom, both as single entities and as a combined force. 

The future wasn’t creating an NPC to fit into an environment; it was the other way around.  The usefulness of an AI within an area came down to the level of abilities they had. For instance, if an NPC was tactical, they would use cover a lot. Place this NPC in a barren area with no cover, voila; kind of wrecked their effectiveness. Luckily, our npcs had backup plans when certain “options” weren’t available to them, but you get the idea. 

At one point in development, we would move objects around within a scene, drop some NPC’s into it and watch would happen: each time a different outcome, even if we left the objects in exactly the same place.  Allowing AI Freedom was hard for me to accept as I was thinking ”how do you handle things like stealth/understanding routes etc?” This was old school thinking and I needed to shake it.  In certain situations, you want an NPC to be regimented (i.e. patrolling a thin corridor or around the perimeter of a building) but, these should be the exception, not the rule.  

NPC’s in an area should be able chose their own directions and behavior settings as long as the player has something they can “read”. For instance, before switching movement direction an NPC may slow down, stop, look around, play idle etc. and then, once ready to move, gesture towards their new direction (look to it and then turn around), this way the player can predict when an NPC is going to stop and which direction they would move in.   NPC’s should be able to move objects in the scene for their own benefit (cover, gain access to higher ground, use of weight etc.), negotiate objects (either dynamic or static), jump gaps, climb ladders, switch weapons based on the logic of their situation, destroy objects to gain a short cut or tactical advantage, drive vehicles and basically everything the bloody player can do…and more.  Once this huge array of choices is created, you designate attributes to some NPC’s and not others, thus creating “behavior types”.  

What if an NPC got into a car, knowing they could destroy a wall I’m using for cover or gain entrance in to my once barricaded house of death?  Let’s start to surprise the player again. Players’ now that if they step over an invisible line or enter an area that an NPC won’t pursue them anymore…it’s not fun or intelligent enough anymore, and to quote a Macedonian “It’s BULLSHIT”.  

I want the adrenaline rush of being pursued by NPC’s just as agile and deadly as me, who think on-the-fly and don’t just stand there to be shot at. These things will force me to think more intelligently on how I attack them, and how I proceed.   As long as player’s have “reads”, our AI can continue to be a lot more advanced, without sacrificing the “control” designers think they need. There’s always a counter to a possible problem. 

The result is simple: more npc options/interactions (either movement or item based) = huge potential for organic WOW moments, or emergent gameplay…or whatever people call it. 


About Haydn Dalton

Creative Lead 30 Years Developing Games

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