The thunderous applause and cheers that greeted Double Fine art director Lee Petty at his GDC discussion spoke volumes on the enthusiasm for Brütal Legend and the interest in its visual style. Petty said that since Double Fine's 2000 founding by the "incredibly handsome" Tim Schafer, the studio's aim has always been to innovate stylistically. "We really want to do something a little bit different than anyone else," he explained. Now, story-based action title Brütal Legend sets roadie Eddie Riggs in an open world featuring multiple factions battling for control. Petty says it has over 80 unique characters, and everything's developed completely in house, aside from the help of a few independent art contractors. So what does "AAA looking" mean, other than an indication of scope? "Creating a giant, open heavy metal world full of titanic scale and landmark with battles so epic the local townsfolk would sing tales of their brutality," said Petty. "But in the process, we also didn't want to lose sight of core Double Fine values." Tim Schafer is responsible for the inspiration and idea of Brütal Legend, and also wrote its "amazing" backstory. "It's a really awesome, awesome document, and really helped form the spine of the entire project and really informed a lot of the creative [direction]," Petty explained. The initial visual inspiration is rooted in the work of fantasy and sci-fi artist Frank Frazetta: "simple brutal forms" with tension and energy, great color sense, contrast and drama without heavy-handedness. The art and imagery inspired by theatrical heavy metal also came to bear: "It helped us not take our mature subject matter too seriously. It reminded us to smile... its unapologetic excesses make it so awesome," said Petty. Finally, the use of hot rod styles as a core part of the world were inspired by the work of Ed "Big Daddy" Roth, who creates monstrous forms and "balls-out hot rods that just feel like heavy metal to us... we looked a lot at his work." Hot Rods in Brütal Legend are a natural formation of the world: "Engines grow inside the earth like some kind of V8 Truffle Of Speed," said Petty. From these inspirations, "our concept artist went batshit" and generated "stacks" of early concepts. "But we still needed to pitch this game. We still needed to be able to communicate a lot of the ideas that we have to publishers." One way this was achieved was by creating factions based on genres, each of which represents part of the heavy metal experience. Psychonauts had a strong indie comic feel -- "but we felt that Brütal Legend's subject matter is more mature. We wanted to approach it freshly, but we really wanted to make sure we stayed stylized and came out with a unique look." Original Eddie Riggs designs were based more on the look of Motörhead's Lemmy Kilmeister and less on the look of Jack Black, who provides the voice performance for the character. But key elements like the vest, tour pass and cigarette have remained throughout iterations of the design. The constituents of the Ironhead faction the player commands in the single-player game were based a lot on 70s-80s heavy metal: Nordic imagery, chrome, leather, long hair and physical strength. Other factions were inspired by the goth look and artists like Hieronymus Bosch. Although the early concepts were more "cartoony" in look, their signature elements have persisted. After developing and focusing the concept art, it was time to sell the idea to publishers. Petty showed the initial pitch trailer, featuring a grim red-violet palette and a handlebar-mustached, guitar-wielding Riggs overlooking goggle-eyed demons speeding in miniature hot rods. "After all this early work, certain elements began to form for the foundation of our style," said Petty. Chief among these was exaggerated, simplified shapes and strong silhouettes -- not only is this useful for faction distinction and visual clarity in large crowds, but it helps keep budgets down while maintaining the vision of a large open-world game. Believable surfaces are "seductive," said Petty. Rich, believable (not necessarily photorealistic) materials make it easier for players to relate to and believe in characters, he asserted. "The other thing is that... materials are probably one of the biggest next-gen features. We all felt if we didn't develop in that way somewhat, we would have seemed a little previous-gen in our title." Value and color contrast were also key to the look and feel. "We [did] not want to be another brown-gray game," Petty explained. "Heavy metal is full of color" -- and color palettes also create stylistic unity. So, starting with the idea of strong silhouettes for character forms, the team needed "clean, easy-to-read faces," too -- The game has over two hours of hand-animated, dialogued cinematics, so performances were important. Simple faces also avoid "tumbling into the uncanny valley." With the number of character types, variation in look is essential: headbangers, gravediggers and battle nuns in the game look strikingly different from one other, for example. When it comes to surfacing, early versions of the characters had painterly, cartoony diffuse textures. The problem with this approach was that the results didn't feel believable. The simple textures "felt flat and not alive," something especially evident when seeing the game in motion. The pixel density was also low: "On high definition screens, they just were too soft," Petty said. So the team decided to evolve the look, keeping the exaggerated forms and focusing mainly on surfaces. "We didn't want our surfaces to dominate our forms. We just wanted them to feel richer." Finally, the idea of juxtaposition is at work in Brütal Legend -- "combining the expected with the unexpected to create the unique," he said. For example, the "bad" album cover art that helped inspire the gameworld's character style, weather-heavy skies and detail-rich land is simultaneously awful and awesome: "It was a constant struggle to know if we were being too heavy-handed or not heavy-handed enough, but I think that tension is part of what makes Brütal Legend unique." "It's important not to imitate your inspirations," he noted, "but to take ideas from them and make them your own."