FIFA 13 Preview: The Physics of Unpredictability
Though ball movement forms half of the unpredictability challenge, player movement forms the other. Success in soccer depends on the creative use of space on the pitch, and FIFA 13 features an all new “Attacking Intelligence” system which transforms the way AI-controlled players move, act, and take advantage of empty space.
In previous iterations of the game, the AI evaluated points on the pitch, looking for space and trying to move players into it so they could receive passes. In the ever-shifting environment of a soccer game, however, this system proved too indecisive — players would constantly stop and start runs as conditions changed.
In FIFA 13, the AI will calculate entire runs on the fly. This ensures that players will arrive in useful spaces at unpredictable but effective times, even if on-field conditions — like a defender in the way — make doing so difficult.
In addition, AI-controlled players are now able to think one step farther ahead. In older FIFA titles, they could only react to the actions of the human at the controls. One player would receive the ball, the players around him would make runs, then he would pass the ball, and the process would begin all over again. In FIFA 13, the AI can now predict the destination of the next pass, triggering early runs designed to provide options to a player who hasn’t even received the ball yet. As Rutter explained, players “now think beyond the immediately obvious: ‘I’m might get the ball, brilliant!’ Now, the next player along will think ‘he’s most likely to get the ball next, so what do I need to do?’”
This system will revolutionize the complexity and unpredictability of building FIFA attacks. It looked particularly impressive in the test bed environment — as players moved the ball around, code strings popped up next to their teammates two passes away, who reacted intelligently and presciently to the flow of the game.
This kind of offensive innovation comes at a cost, however. To balance the impact of Attacking Intelligence, the developers had to shore up the Tactical Defending system, which was introduced in FIFA 12. Channon emphasized the importance of that improvement, which redesigned tackling and positioning to give players more defensive tools: “It’s half of the game. You’ve got attacking and defending, and we completely changed how that works.”
In FIFA 13, defenders can now push, pull, and block attacking players with greater effect, deploying complicated physics — based on simulated human musculature — to generate unpredictable outcomes when two opposing players come together.
These defensive changes demonstrate the difficulty of the developer’s task — change one system, and everything else has to change with it. Tactical Defending and 1st Touch Control work in harmony; defenders can now use their bodies to force attacking players into taking poor touches and off-balance shots. But because physical interactions between players are now so unpredictable, the FIFA team had to completely redefine the way referees call fouls.
In an interview, detail man McHardy explained:
“Rules used to be a very small feature that we considered every year, because they were cut and dried. We had physics that resolved the collision in one frame. In that single frame, when players came together, you knew what was going to happen in the future: he was going to stumble, he was going to fall. You knew what time the infraction took place, and you knew if you had touched the ball or not.
When we brought in the Impact Engine in FIFA 12, that completely changed the way we had to look at foul situations, because identifying the point in time when the infraction took place became an infinitely more difficult problem. Players didn’t necessarily stumble or fall immediately when they were touched. You can imagine if someone comes in and rubs my leg a little bit; second frame happens, pushes me a little further; third frame, fourth frame. As you keep going, maybe 10 frames down the line is when I actually stumble. At what point in time did the foul take place?
It’s trying to rewind time to find out: when did that actually happen? You can imagine I’m running beside you and our arms touch on Frame 0. On Frame 7, I slide tackle you. So, the collision actually started on Frame 0, but we didn’t really care about the fact that our arms touched. We had to go through all that information to find out what was significant.”