Computer Graphics World

being crushed in the compactor of a garbage truck, the team wrote original programs. Making Jack's movements mimic those of the player and the Wii Nunchuk de- manded an extreme degree of flexibil- ity, rotational freedom, and realism in his animations. With a swiping motion of the controller, the player can hack through an opponent with the chainsaw. By twirling it, the player can swing a foe over Jack's head before hurling him into an object. "It's a constant challenge," says Yamanaka, "to link the character's movements to the player's so that he responds perfectly." To meet that challenge, the team created nearly 2000 animation cycles for all the bi- pedal main characters, including Jack, in Softimage. About 60 percent of those ani- mations were motion captured using systems from Vicon and OptiTrack. To blend those cycles smoothly, Yamanaka says riggers used Hermite interpolation, a method of inter- polating values between key points to form smooth curves, in the blending system. Aside from linking Jack and the gamer's movements, another constant challenge was maintaining movement in the nonplayer characters. When the movement stops, the character dies, as the old animation adage goes. "We had to keep the enemies doing something all the time," says Yamanaka, "be it making them punch each other, act fright- ened of something, or just laughing. ere isn't a single moment anywhere in the game where the enemies are standing totally still." Effects in Red "Polo with chain saws" is how Jack de- scribes the game he finds himself part of. From golf clubs to baseball bats, spiked clubs to lampposts and knives, Inaba and his team developed Jack's arsenal around melee weaponry designed for close-quarter combat. During the conceptual stage, In- aba analogized Death Watch to a baseball game, wanting the player's actions to feel like those of a batter, which would, in turn, be organic to the Wii. "To accomplish this, we avoided guns and the infrared pointer. We wanted the gameplay to be more intuitive and re- freshingly different than other titles for the Wii," Inaba says. "Gun violence is too common in video games, and worse, it's visually boring. Over-the-top violence was our mandate, and the only way to achieve it was through an increasingly creative and sometimes bizarre set of weapons." Such weapons, however, are bound to make things messy. Blood is cheap in Varri- gan City; it's everywhere, not just as a con- sequence of violence, but as the linchpin of the art design and the central metaphor for the game's theme of bloodshed for en- tertainment. e group created the blood splatter in Softimage using a combination of meshes and particle animation. How- ever, because there were so many variations in the kill moves, the team had an espe- cially difficult time making the trajectory and movement of the blood flow unique to each move. "Imbuing the blood with a sense of real- istic movement was extremely challenging, because in a world that is only black, white, and red, the only tool you have to create movement is movement," says effects de- signer Yoshikazu Hiraki. "If you want something to stand out in a monochro- matic world, you have to make it move. To that end, we often had to increase the vol- ume of the particles and the rate at which they're duplicated." For the splashes of blood that stain Jack and his enemies, artists modeled several meshes in Softimage, which are then laid over the character geometry during game- play. For rain, smoke, dust, fog, wind, and fire, the artists again used the same system of particles and polygonal meshes. To cre- ate the smoke, fog, and dust, they dupli- cated the particles, created meshes from which to emit them, and then added wind effects to make the particles drift along the vectors. For the huge plumes of billow- ing black smoke, they added a silhouette to each particle aggregate to separate them from the rest of the smoke cloud. Programming the blood spray from one body to another or from one surface to another was crucial to the game's success. at challenge fell to programmer Masu- mi Tarukado. If the spray reaches a wall or trickles to the ground, Tarukado's program uses four collision detections to determine if the liquid hits the receiving surface. If all four are affirmative, then the surface is stained blood red with a texture map. If blood splashes against another character's body or if Jack is struck by a backlash of blood, Tarukado's program searches the character's mesh for the polygons that would be stained, and then creates UV and vertex indexes for them, which are then used to place the blood meshes onto the character. With the Wii, it is possible to also have unique indexes for each vertex or set of UV coordinates. erefore, the engine can cre- ate the blood mesh using vertex informa- tion derived right from the character mesh, or it can use UV information, which it then uses to draw the blood mesh using newly created UV coordinates. Using UV infor- mation, however, can cause Z-fighting, in which the blood mesh can penetrate the All the environments and characters are rendered with simple black-and-white textures, while the effects, such as smoke and explosions, required a post filter in Softimage. June 2009 30 n n n n Gaming

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