At one point in the development of Watch Dogs, a problem surfaced during the game's performance capture process. It had nothing to do with the elaborate array of cameras Ubisoft had rigged up in its Montreal capture stage, nor did it involve the computers used to turn those acting performances into in-game character animations. No, this problem was of a slightly less technical nature.

There were no pockets on the actors' suits.

Normally, this wouldn't be an issue. But that day the Watch Dogs cinematics team was shooting a scene that required the game's main character, Aiden Pearce, to reach into his pocket and pull out a smartphone. Pearce is an urban vigilante with a mastery of electronics bordering on terrifying, so even an ordinary movement such as this had to be executed with careful gravitas.

And so the crew had to think of a solution. Could they sew in pockets? Nope. The spandex unitards actors wear on these shoots are adorned with hundreds of tiny sensors designed to register movements large and small, but only so long as the cameras can see them. Velcro? Too awkward. A belt holster? Maybe if Aiden were a middle-aged real estate agent.

Then it came to them: magnets.

Aiden Pearce totally not checking his Twitter mentions.

The team would fashion a small plate and attach it to the suit of lead actor Noam Jenkins. On the plate would be a magnet strong enough to keep the prop phone attached, but weak enough for it to be detached with a gentle upward slide. A bit like pulling a phone from one's pocket.

"It was the stupidest little thing," recalls cinematics lead Lars Bonde. "But those are the small details that make the game feel so much more real."

In most games, a detail like this would be considered trivial. But there's nothing trivial about the smartphone in Watch Dogs. As a hacker capable of wirelessly tapping into Chicago's city-wide surveillance system, your phone is your primary tool for interacting with the gameworld. Beyond that, it's also a thematic focal point in a story revolving around instant access to information and the ways that power can be abused. Smartphones and their place in modern society are concepts that sit squarely at the heart of Watch Dogs.

And yet, that wasn't always the case. In 2009, a team at Ubisoft Montreal was assembled to create a new open-world franchise. With Assassin's Creed covering the historical settings and Far Cry taking care of the rugged outdoors, this early team elected to focus on the modern urban landscape.

Smartphones and their place in modern society are concepts that sit squarely at the heart of Watch Dogs.

"The only mandate we had was to work on an open-city game," says creative director Jonathan Morin. "So one of the big things for us was reflecting on the urban life of today."

"We chatted a lot about ideas for the game, and the one subject that kept coming up was the impact of technology on our daily lives. Back then, smartphones were somewhere in between pop culture and geekness. My family didn't know what they were. They were just emerging, but it was obvious they would become something big."

Morin and his team didn't know how big smartphones would become, but they had a sneaking suspicion this was a technology whose impact would only grow stronger over time. That sounds like a safe assumption now, but remember that in 2009, BlackBerry still held the majority of the smartphone market share. Apple's stock price began the year at a whopping $450 less than where it sits today. A lot has changed since then.

In pondering the effects of smartphones, the Watch Dogs team became fascinated with the ways in which privacy would be affected by our increasingly connected world.

"It's very rare when you start a project and you have this canvas of possibilities," says Morin. "Facebook, social media, privacy--it was so easy to go into hour-long discussions about those subjects. That fascination early in the project became a weapon for me to [go to management] and say, 'Let's do something where fun can collide with thinking.'"

You're not always the one doing the hacking.

Given the focus on privacy, it was only natural that Morin and his team looked toward Chicago as the game's setting. With its vast network of surveillance cameras, Chicago is the most-watched city in North America. Last October, Polygon published an excellent report on the Windy City's surveillance network and pegged the number of cameras accessible by the city's Office of Emergency Management and Communications at "as many as 24,000." This includes cameras installed by the Chicago Police Department as well as security cameras in private buildings where the owners have voluntarily granted surveilance access to the city.

This surveillance infrastructure became the inspiration for the central operating system that powers Watch Dogs' version of Chicago. Dubbed ctOS, this operating system extends far beyond cameras; it controls everything from traffic lights to steam vents. As Aiden Pearce, you're able to cruise through Chicago hacking objects on the fly, triggering massive pileups at intersections to flee from the police or tapping into the system's crime prediction mechanism to stop crimes before they even happen.

The original idea for this was a lot more abstract. One of Morin's earliest presentations to Ubisoft management conveyed this structure through a single image: a finger hovering above a red object accompanied by the phrase "Control an entire city through the press of a button."

Morin knew what type of scope he wanted to build for the game, but was less certain about what exactly the game's main character would do with that level of access. So the team spent time working on who this character was, what his ambitions were, and how far he was willing to sidestep ethical boundaries to get there.

Drag the slider above to compare two early concepts for the smartphone interface.

"When we started to talk about the game, we asked, 'What should he do while he's at his safe house?'" says Morin. And it's here that he takes on a wry smile: "Well, he should be monitoring everyone. He should know about everybody."

"The fantasy has always been, what if you can access everything? What if you were the invisible man in the room?"

This focus on surveillance soon came together with that initial fascination around smartphones to form the game's profiling system. This mechanic allows you to tap into the city's repository of personal records and surveillance data to form a quick impression of every single pedestrian in the city. Details like profession, salary, and Web browsing habits flash across the screen as you pass strangers on the sidewalk. Find someone especially interesting, and the game will often let you learn more about that person by listening in on phone calls and remotely hacking his or her text message logs. And it's all done thanks to Aiden's smartphone.

"We wanted to give that sense you get when you sit on a bus and overhear people talking about whatever," says lead story designer Kevin Shortt. "Snippets of conversations. You just hear enough to go, wow that's a fucked up relationship. And off you go."

The fantasy has always been, what if you can access everything? What if you were the invisible man in the room? Creative director Jonathan Morin

"Sometimes you get rewards, or you get opportunities for a mission. But a lot of times you're just getting a snapshot of that person and filling in the blanks."

Profiling is a gameplay system aimed at breathing life into the city of Chicago, tapping into the idea that we're all carrying devices with a wealth of personal information, and anyone with enough technical know-how can come along and read our life's story if they're so inclined.

Unsurprisingly, building a city's worth of cell phone owners was no easy task. It began, as so many projects do, with good old-fashioned research.

"We have a cafeteria in the building that overlooks an intersection," says Bonde as he describes Ubisoft's Montreal office. "This is the artistic area of Montreal, so you have a lot of foot traffic going to cafes and all that. So we just looked at people. How do they come to a stop at a red light? Do they bring out their phone while waiting? Do they cross while talking? It's observe and learn."

Other members of the team would watch people riding the Montreal subway on their commute into work. How did they carry on phone conversations while in public? How many of them were playing games? What were the chances one of those games wasn't Angry Birds?

"You start looking at people and their phones all the time when you work on Watch Dogs," jokes Morin. "You start becoming as weird as Aiden."

Who needs an umbrella when you've got technology?

Another challenge lay on the writing side. Watch Dogs' profiling system dynamically provides character stubs for non-player characters, but somebody's got to write those stubs.

"We had to create a lot of content," recalls Shortt. "A lot. If the fantasy is I can hack into your phone and read your text message, we've got to pay that off. If you see that text message once, you can't see it twice."

But for as challenging as writing that content was, Shortt believes the payoff has been worth it. Even if it shows up in surprising ways.

"I was in combat one time and I had my profiler on," says Shortt. "These guys were trying to kill me, and I was trying to kill them. Then this one guy comes around the corner, and his profile tells me he's a newlywed. And I'm like, awww... Blam! [Laughs] And that's what our goal always was. Let's take these NPCs and make them characters."

Even with these systems in place, Watch Dogs is still very much an action game. There are guns to fire, cars to drive, and a city's worth of criminals and heavily armed security guards to deal with. And throughout all this, hacking remains a constant theme.

Everywhere you go, you'll find a context-sensitive white outline drawing your attention to objects you can hack. If you're in a police chase, you might hack a drawbridge just as you pass over it in order to lose the cops on your tail. If you're sneaking into a ctOS facility, you might hack a window washer to elevate you up to a second-floor window before accessing the security camera network to get a feel for the guards' patrol routes.

Hello? Yes, this is Watch Dogs.

The Watch Dogs team worked hard to maintain believability within the ctOS fiction, consulting with Russian security firm Kaspersky Lab to ensure that none of the various hacks were too extravagant. But the one area where the team will admit it took creative liberties is the speed with which these hacks are done. Nearly everything in the game can be hacked with a single, instantaneous press of a button.

But therein lay the challenge: how do you provide the player with quick hacking opportunities while giving substance to the gameplay? To lead designer Danny Belanger, it's all about building a complex web of interlocking gameplay systems so that no one hack is an immediate victory over the AI. Instead, as Belanger sees them, these hacks are the initial flick of a finger in a line of dominoes.

"The core for us is having a simple way to connect and interact with the world," says Belanger. "But by doing that, it has to be useful and not feel like a win button. It's a window of opportunity. It's a win against one guy, but the other AI might become aggressive and start searching, and that puts you in even more danger. And then you chain the other hacks to distract them. So it's all about risk-reward and giving people windows."

You start looking at people and their phones all the time when you work on Watch Dogs. You start becoming as weird as Aiden. Cinematics lead Lars Bonde

This puts a lot of pressure on the AI. The guards and criminals Aiden deals with need to know what's a coincidence and what's just plain fishy. A steam vent malfunctioning and scalding a guard is one thing. A steam vent malfunction followed by a car alarm and then a citywide blackout is something completely different.

"If the player doesn't respect our AI, he won't take the time to use stealth or hacking," says Belanger. "Maybe he's played a lot of shooters and says, 'I'll just shoot everything.' And if he succeeds all the time, why would he change? Why would he try hacking? We want him to have a certain fear of the AI."

That means designing an AI system that's both aggressive and a little bit unpredictable. These are not common events that Aiden is using his phone to trigger, and Belanger doesn't want common reactions from the guards.

"When you do a hack and you interact with the world, you want to feel like these are humans. It's a bit unpredictable. Having some chaos and noise keeps things interesting. It creates gameplay stories."

Ultimately, the Watch Dogs team knows that giving you the opportunity to create stories is the central appeal of an open-world game. And by rooting its fictionalized world in the sort of technology that influences our everyday lives, it's hoping to make those stories even more relevant.

"I have a 7-year-old daughter," says Shortt. "She knows I'm making a video game, but she doesn't know what it is. One day I brought home a little statuette of Aiden, one of those little character figurines. She asked [while pointing at his phone], 'What is that?' And I said, 'That's his weapon!' She was fascinated by that. And that's what I love about the phone."

"The phone is his primary weapon, his primary tool. It's pretty powerful. And I think that reflects the world we've entered. These things are powerful."