Contact Sport
Issue: Volume 34 Issue 1: (Jan-Feb 2011)

Contact Sport

From tennis to golf, football to hockey, snowboarding to skateboarding, sports-themed video game titles continue to grow in popularity, enabling the former high-school basketball player to relive his glory days on the virtual court, a football fan to become part of his or her favorite NFL team, or even a newcomer to step onto the ice for the first time. No matter the allure, there is a wide range of current-generation titles that put players into the sporting game of their choice.

While there are a number of developers and publishers who play in this particular genre, there are two—EA Sports and 2K Sports—that dominate the market. EA Sports’ Fight Night 4 is a knockout when it comes to boxing. A strong player in this realm, THQ, is the current ringleader in terms of wrestling, with WWE SmackDown vs. Raw. When it comes to karate and fighting games, a number of publishers have kicked things up over the years in the form of offerings such as Midway/Warner Bros. Interactive’s Mortal Kombat. Without question, the big successes in sports titles are linked deals between the developers and sports franchises (the NFL, NCAA, NBA) or individuals (Tony Hawk, Tiger Woods, John Madden)—games that feature real leagues, real teams, real players, real competition.

Working toward the premise of “the more real, the better,” EA Sports recently released MMA, a mixed martial arts title that EA Tiburon computer graphics supervisor Kevin Noone describes as a true fight simulator rather than a mashing game. “From the start, creating completely realistic human fighters was our top priority,” he says. “In the past, fighting games have tended to be more about mashing a lot of buttons than simulating a real fight. For EA Sports’ MMA, not only would the skin, hair, sweat, and blood of the fighters need to look absolutely real, but the contact and overall interaction of the fighters would be a fully accurate simulation.”

Fight Club

With the rise in popularity of mixed martial arts, it was only a matter of time until EA threw its expertise into the ring, creating a title that depicted the gritty sport. Known as ultimate fighting, no-holds barred, or cage fighting, the sport combines the techniques from boxing, martial arts, and traditional wrestling. Competitors can kick, punch, tackle, grapple, and wrestle in any combination while protecting themselves using these same techniques. This wide range of motions, along with the unpredictable nature of the sport, would present many complex challenges to a development team that ventured into this sport. It was not a game that could be rushed.

As a matter of fact, when Simon Sherr, animation director at EA Tiburon (Orlando, Florida), began working at the company more than seven years ago, he and others pitched the idea of making an MMA title. But, the timing wasn’t right on a number of fronts. But then, a few years later, things started to change. The popularity of the sport took off on a global level with leagues like Strikeforce. Then former VP of Microsoft’s Interactive Entertainment Business Division, Peter Moore, a fan of MMA, jump over to head up EA’s sports division. Perhaps most important, ANT—EA’s propriety middleware suite—was maturing and had reaped success on titles such as Fight Night and NBA Jam.

Several years ago, Sherr himself was one of the primary inventors of ANT, a game engine for EA that would enable internal teams to build just about any type of fighting game, having pitched the concept for the tool in 2004. The idea was to globalize the animation tools within EA to save time and money. After kick-starting ANT development, he later led the Fight Club team—a collaboration among EA Chicago, EA Canada, EA Japan, and EA UK (the RenderWare physics guys)—to build a fighting engine inside ANT, which, at the time, was already in existence but still in its infancy. The fighting engine consisted of a layered visual state machine tool set, a variable asset system (later called “game states”), character physics, procedural awareness, and a robust character interaction engine and targeting system.

Electronic Arts launched a new sports franchise with the release of MMA, a mixed martial arts game featuring fighters who look like their real-life counterparts and move like them, too.

“[ANT] is kind of a fight-game engine, but it allows us to build whatever we want. It has a lot of functionality,” says Sherr. ANT contains a modular animation framework for which the EA developers can build plug-ins that are very specific to a certain genre of game, whatever that may be. Initially used for Madden NFL 2006, followed by Fight Club and even NHL 2007 (using Fight Club’s state machine for skating and analog stick handling), ANT was vital in making NBA Street: Homecourt and Def Jam Icon—the first titles built using the full suite of character interaction tools and the Fight Club state machine. Currently, ANT is being tweaked by the Battlefield group for the third-person shooter.

Three years ago, when Sherr was convinced that the engine had matured, he, along with MMA creative director Jason Barnes and a handful of others, began working on a prototype to use during their creative pitch for an MMA game. “We wanted to do a true fighting simulator because a lot of us felt it had never really been done before,” says Sherr, himself a former kickboxer. “As with any EA Sports game, it was important for us to stick with what our brand is really about—to make the sports game fun and to teach people about the sport.”

According to Sherr, players expect compelling realism in titles from EA Sports. To that end, the trio sold EA execs on the concept and began assembling a small team (by EA standards) from within and outside Electronic Arts. By design, most were former martial artists, boxers, or fighters of some type—all of whom were passionate about the title. “We really wanted to create something that made us feel like we were stepping back into the cage, or ring, or whatever it was,” Sherr adds.

Move in the Right Direction

According to Sherr, the team had already done groundbreaking work with games like Fight Night, but MMA promised to be an entirely different animal. “MMA is an anything-goes style of fighting, which is much more fluid and unpredictable than Fight Night,” he notes. “From a design standpoint, we set out to create a peer simulation fighting game, giving the players absolute control. We took punch control and went way, way beyond.”

With Fight Night (developed by EA Canada), the team took ANT—which already existed—and built a suite of tools internally so that the engine could support specific fighting: in that case, two-player interaction. EA Tiburon began MMA using Fight Night’s version of the ANT tool, rather than the Madden version employed for building the prototype.

For MMA, though, the team had to build even more tools. “It’s the first game EA has made where we can do simultaneous two-person animation. That was a big part of what we had to create with our technology for this game to work,” says Sherr. “We upped the quality of the two-player interaction system to allow for independent movement and interaction.”

The game contains groundbreaking animation through the use of Relative IK, developed at EA.

The key to MMA’s success is the realism of the action. There is a sense of complete and consistent contact between the fighters: They move independent from each other but react to each other’s movements in strikingly realistic ways. Muscles twitch and flex during action; they ripple and undulate when hit. And, in a unique move, there is no “roll of the dice” anywhere in the game—that is, random numbers will not determine fight outcomes. “When you win a fight, we want you to win it. And when you lose, we want you to know what you did wrong and what you could have done better,” Sherr says. “You are not a victim to a random dice roll.”

Sherr notes that there are many simulation games on the market that actually simulate the results. “We discussed the differences between a simulation and a simulator; we wanted a simulator, which allows the users to feel like they are in complete control and can do anything they want to do, including the wrong things. We will teach them what they are doing wrong, rather than force players into doing only the believable things that a well-trained fighter would do.”

As a result, a player’s personal strategy is dictated by the skills and attributes of the fighters being used, as well as the player’s own abilities, reflexes, and reaction times. This, in turn, determines which fighters the player will have more success with during matches. “The fighting can be brutal, but it is very strategic and cerebral. You need to play to your strengths and your opponents’ weaknesses,” Sherr points out.

The characters that ship with the game are digital doubles of real-life, triple-A league MMA fighters from around the globe; also included is a customizable fighter. And, just like in the real world, each league from around the globe has its own setting that will dramatically change how fights play out—whether they are in a ring versus a cage, and so forth. The same holds true for the fighters themselves. Because they are based on real-life people, those fighters’ styles and capabilities are integrated into their virtual alter ego.

The artists and animators relied on ANT, EA’s universal middleware engine. ANT contains a modular animation framework for which an EA team can develop specific plug-ins for their particular title.

“There are some fighters who are really good at staying on their feet, and they force their opponents to fight standing up. Or, there are some who are good on the ground, and they force some of the most dangerous strikers in the world to spend an entire fight on the mat,” says Sherr. “We have taken that same approach and integrated that strategy into the game, with tactical feedback given to the player to steer them in the right direction.”

Fighting with Character

Each game character is created primarily in Autodesk’s Maya and animated using Auto­desk’s MotionBuilder. “We start and end in MotionBuilder,” Sherr says of the software. “The tool is animation’s equivalent to Photoshop. It gives animators complete control over posing and timing. We start the animation process with motion capture, but for us, it’s almost like shooting visual reference.”

That motion capture was acquired using a Vicon system set up at EA Canada as well as at the Florida Interactive Entertainment Academy (FIEA), located at the University of Central Florida campus in Orlando. The group also used a portable mocap suit from Xsens, which proved especially useful during the prototyping phase, for secondary movements, and for the referees. The mocap data was filtered through MotionBuilder and then exported to ANT.

The character skeletons comprise just under 100 joints, in addition to hyper-corrective joints: sets of 20-plus joints used to do muscle deformation, fix shoulders, twist forearm joints, and perform all the “extras,” such as chest jiggle.

The crew used the base MotionBuilder rig, the HumanIK rig, to move the characters within MotionBuilder and within the game itself. “The animation rig we animate on is the out-of-the-box MotionBuilder rig,” explains Sherr. “The animation skeleton has the default MotionBuilder joint set, and we added on top of it a set of target joints. When we bring the animation rig into our game, we have it broken up into non-hierarchical sub-rigs. So we started with the bones we move manually—shoulders, knees, elbows—and move on from there.”

As Sherr explains, the entire game is driven by the animation systems rather than specific code. “That’s what makes it so unique. We use game-state scripting to build complex behaviors, animation branches, triggers, and so forth,” he says.

The game contains 900 states, or individual movements a character can perform. Those states are pressed down into three distinctive modes: stand up, clinch, and ground, which in turn are broken up into smaller states. EA’s locomotion system handles things like directional changes, character fatigue, and so on, which are then layered on top of the animation. “It is like Photoshop, with a layers system used to mask alpha channels, only here it is a way to mask different skeletal joints, layering in animation either through adding, over­riding, or blending,” explains Sherr.  

The title features various venues, many of which are modeled after actual locales in the US and abroad. The game characters follow the fighting rules and styles dictated by the virtual country hosting the event.

ANT manages all those layered interactions to create the final frames—no small job considering there are thousands of animations in the game. “Animation-wise, we are officially the largest animation game that EA makes,” Sherr proudly points out.

Sporting so many animations, however, comes with some major challenges. “We have all the problems of a wrestling game, all the problems of a fighting game, and all the problems of a boxing game—all wrapped up in one title” says Sherr. Because MMA fighting involves such a wide variety of moves, they all had to be incorporated into the game, along with subsets of those moves. “You wouldn’t believe how quickly that can balloon up into a massive volume of animation,” he adds.

Smooth Moves

With the focus on realism, it was imperative that the characters move realistically and logically, despite the unpredictability resulting from so many movement options. Moreover, the fighters have to move independently of each other but still react to each other’s movements in a plausible way. Accomplishing these ambitious animation goals, particularly between characters of different sizes and proportions, required believable contact between the characters. To this end, one of the groundbreaking developments in the game was the introduction of Relative IK (RIK), which uses a combination of HumanIK and MotionBuilder to forge complex relationships between the characters. Its use was twofold: to solve player-size scaling issues (it will adjust how player contact works depending on the size and girth of the opponents) and to prevent a player from losing control of the character (it will enable the characters to fight simultaneously by adding multiple layers of animation onto the characters using the Photoshop-like methodology).

When the MMA opponents connect physically, that contact has to be precise—no easy feat when the characters can vary greatly in size and girth. This issue was resolved with non-uniform scaling, which involves changing the length of a character’s limbs and joints to convey different body sizes and proportions, and then applying the animations to the scaling rig using HumanIK.

The player’s target joints—key points on the body that move according to body type—are linked to the surface of the skin, allowing the animators to grab or punch positions on the body that are on the surface and totally independent of the girth of the fighter. “So if the character’s stomach or chest becomes larger, we can still stretch the actual surface of the skin,” explains Sherr.

Unlike most other fight games, MMA enables players to maintain control of a character during two-player animation situations while still having single-player interactions align with the other fighter—all without incurring cosmetic issues. For instance, if you are being grappled or pinned, typically you cannot fight back. But the two-person animation in MMA enables the characters to fight simultaneously—so if you are being pinned, you can still punch your opponent and land crushing blows. “The fighters still could punch and do all the things they normally could do independently of one another, but now they could do it at the same time as the opponent did.”

Once the animators developed a polished, two-man animation, they devised all the important contact relationships between the fighters. “The fact that HumanIK is integrated into both ANT and MotionBuilder is a huge plus for us because the interoperability is essentially seamless,” says Sherr. “I can go into MotionBuilder and add auxiliary effectors on one fighter and parent them to his opponent. For instance, if I am grabbing him by the head, twisting his arm, rolling him over, I can create auxiliary effectors for those contacts, all of which makes transitioning between those positions more realistic.” Those auxiliary effectors are then exported with the animation, along with each effector’s location relative to the joint to which it is parented.

Another way the team was able to get the CG characters to anticipate and react like skilled fighters was through procedural awareness, developed for EA Sports’ FIFA Soccer franchise, which eliminates what Sherr describes as the “dead cow stare” typically found in most fighting games. “Using procedural awareness, we can give our characters a lot more personality,” he says. “With eyeball tracking, we can fine-tune how each body will react to a specified target in space as the eye follows it.”   

Lastly, the animators used HumanIK to develop realistic foot pinning to determine precisely where and how each fighter’s foot would be planted for a particular move.

A Champion is Crowned

With a totally committed team, defeat in the form of a mediocre game was not an option. In all, the crew spent nearly two and a half years in full-time production—more than double the time a team usually gets at EA—making sure it delivered a product of which they could be proud. “When we started this, we convinced EA that we had to do it right, and that it would take time,” says Sherr. “We wanted a small team who would work on it for a long time, and that is what Peter [Moore] gave us. He was dedicated to the idea that this was going to be EA’s next triple-A title. It’s not every day that you launch a new sports franchise, but we didn’t want to release a game that felt like a first-year title.”

Over the development time, the crew expanded from a dozen people to close to 70 at the end. “I’ve never worked on a game where we have been able to apply this level of polish,” Sherr adds.

And throughout that time, the crew had kept their eyes on the ultimate prize. “Everything I have done with EA to date since I started in 2003 was with this game in the back of my mind,” relays Sherr. “I am very proud of what we have done with MMA, and even more excited about where we are going next with it.”

Without question, though, it will be the game players who will be the real winners as they step into the virtual arena for a truly unique MMA experience.

Karen Moltenbrey is the chief editor of Computer Graphics World.