Search form

Animating For Games…Naughty Dog Style

While completing animation for gaming is similar in many ways to other forms of animation, there are some very particular concernslike console memory and interactivity that need to be kept always in mind. Bob Rafei of Naughty Dog explains. Includes QuickTime movie clips!

rafei01_jak.jpgrafei02_daxter.jpg

Two pages showing renditions for Jak (left) and Daxter from the bible for the game. Complete character development for characters includes final color drawing, turnarounds, action poses, size comparisons and facial expressions as shown here. All images: Jak and Daxter: The Precursor Legacy is trademark of Sony Computer Entertainment of America, Inc. © 2001 Sony Computer Entertainment America, Inc.

If you have the QuickTime plug-in, you can view a clip by simply clicking the image.

Imagine that you are a creative resident of Games-ekhistan and have to pack a one size fits all suitcase for a long trip AND you have to share this space with other family members. Your vehicle is a copy of the only model available in this rugged frontier-like country. Of course, you have specialists in your group that can tweak, or even rebuild, the cars engine from the ground up to modify performance. Now, if you happen to be from the neighboring Toon-town, FX-ville or Feature-land, you are accustomed to having the biggest vehicles and suitcase money can buy for your trip. However, you have to travel with all your extended family since more of them are needed to keep the bus rolling.

rafei03_daxter-morphs.jpgrafei04_explorer-morphs.jpg

Maya grabs of Daxter and Explorer morphs show asymmetrical face targets for facial animations and front and side schematic drawing for modeling.

I often find myself using this horribly goofy example as a way to explain to friends and family what it is I do at Naughty Dog, Inc. (NDI) and why game development is not exactly the same as working with film or TV. What you might, or might not, have gotten from this example is that one of the main concerns of game development is memory allocation and data storage. There are only a certain number of polygons drawn on the screen, and calculations in any given frame, or frame rate will drop. Without the invisible work of the programming staff, we the artists would have very little room for any contribution of our crafts.

I also find myself explaining that besides the apparent technical limitations, another major attribute of games is that it requires an active versus passive audience participation. No two players will have the exact same experience playing the exact same game. Gameplay is paramount over any story. IF there is a story it is only there to propel us forward to the next level. If the player doesnt like the feel of the controls or the play mechanics, the best-crafted story sequences will not save the game.

rafei05_caves-chamber.jpgrafei06_caves-discovery.jpg

Production sketches like these are the first step in building 3D game environments.

Each generation of consoles has further expanded our boundaries. Since more stuff can pass through the pipe, visual advancements become the first noticeable difference, followed by the individual style between developers. Therefore, production design has become a required link in an ever-growing chain. Before the original PlayStation days, Jason Rubin and Andy Gavin, the co-founders of Naughty Dog, Inc., were doing the art and programming respectively, pretty much from the garage. When I joined Naughty Dog in early 1995, we went on to finish our first title, Crash Bandicoot, for the PS one as a team of eight. As production work started on our first PS2 title, Jak and Daxter: The Precursor Legacy, in January 2001, we went from a company of 15 to 36 and today we are 44. Our decision to try something bigger than we had ever done before resulted in the (and some veterans would say the unfortunate) necessity to specialize tasks in our pipeline. We were now able to attract full-time artists foreign to game development, who have such roles as production designer and story sequence (FMA) animators. Some of these talents came to us from places like Disney Feature Animation, Digital Domain and other non-gaming production houses.

rafei07_jak-bonesonly.jpgrafei08_jak-wireframe.jpgrafei09_jak-textures.jpg

Jak's kinematics is setup and rigged using Maya.

Jak and Daxter: To Do List

Expanding on our experience in the character action genre, we wanted to develop the most fluid and seamless animation possible, to give Jak, and his wisecracking buddy Daxter, a life of their own. For better or worse, we decided not to give Jak a voice since it was believed any voice would further remove the player from playing as Jak. Daxter was to be a squash and stretch friendly character that would drop unique hints to guide the player within the world they were exploring. The enemies that the duo would encounter were to be just as elaborate in their animations and have the intelligence to react to Jaks moves accordingly. No longer would the enemies be constrained to a certain path, but rather would be able to track Jak and decide how to chase him around obstacles. The animated story sequences had to draw in the same in-game engine and needed to be good enough cinematically to stand on their own. We also wanted the player to break out of the conventional linear progression of entering levels and allow them the freedom to explore the whole world from end to end uninterrupted. Borrowing from theme park construction, we placed a unique giant background element in each level in order to lure the player in that direction. The levels lighting was to cycle through different times of day in a real-time 24-minute-day cycle. The game camera had to be smart enough to track Jak, yet not have any sudden movements that could make the player nauseous. The music had to match the tempo of the action. Localization for all territories (U.S., Japan and PAL territories) had to progress concurrently in order to make release dates that were one week apart for each territory...AND it all had to be done in about 18 months.

Here is a little perspective: Crashs model was roughly 500 polygons. There was very little room for detail or any use of complicated shapes. The hands, for example, needed to be mitts. Jak and Daxter, however, are about 5,000 polygons combined. We were now able to model individual fingers, some description of anatomy and facial features, which would look good enough for FMA sequences...up to a distance. Weve since increased the resolution of the characters for such sequences to around 12,000 polys, which allows us to budget more polys in the new models head or facial features alone, than were in Crashs whole body. Some of these scenes involve up to six of these FMA models, along with a few regular resolution characters placed at some distance from the camera, totaling around 100,000 polys per frame just for the foreground elements. The camera can now be pushed in close enough to a face to have it fill the whole screen without looking too polygonal.

In-Game vs. FMA Animation

Any art in the game can either fall into a background or actor category. Actors are any geometry that is rigged to a skeleton for the purpose of animation. This can include a simple door, with one bone used for rotation, to the most complicated characters and bosses (the most challenging and unique enemy set ups). All actors fall under either in-game (the majority of actors in the game) or FMA. In-game actors need to be the most efficient and leanest in their use of bones and polys, allowing us to maximize our rendering possibilities. The kinematics structures for the in-game and FMA actors are mostly the same, with the exception that bones that are not pivotal to the animation (like pinkies, toes or straps, for example) are not processed on run time. This allows us to recycle states of animation, when appropriate, for consistency of style between in-game & FMA, and yields better productivity. The level-of-detailing (LOD) of actors is necessary in order to minimize polygons based on distance away from the camera.

rafei11_jakDaxter_walk.jpg

rafei12_jakDaxter_run.jpg

Jak and Daxters in-game walk and run cycles. The pressure exerted on the controller stick can dictate the ratio of blending between any combination of animations like these.

Our proprietary mesh tessellation routine for background geometry is a crucial part of LODing, which allows us to have so many actors on screen at once. The coolest aspect of our in-game animations is our animation blending technology. This powerful technology allows us to blend between multiple animations of the same kinematics structure. For example, Jak has a standard run cycle, but he also has a run uphill and a run down hill cycle. Based on the grade of the terrain that he encounters, we can blend the standard run into run up or down hill. Depending on the pressure exerted on the controller stick, Jak can start from a walk cycle and progress up to his run cycle. The tempo of the run cycle is also modified in parallel with the controller pressure. At half pressure the player will see a sort of jog, walk and run. The blending is also used to smooth out any transitions into other actions, like jumping or punching, at any given frame. This means we do not have to worry about keeping track of branching points from one cycle to another, which in turn cuts down any lag in player response. However, the price for responsive controls results in no allowance of anticipation in the animations. The polish on the animations could be placed in the follow-through actions at the end of the cycles, when appropriate, for instances where the player allows a gap of time before the next action is exerted on the controller. These uses of the kinematics blending gave our in-game animations more life and fluidity than existing standards.

rafei13_sizecomp.jpgrafei14_sizecomp.jpg

Size comparisons between the different Jak and Daxter characters.

Our FMA sequences are straightforward scenes animated to voice recordings that expand on the story while giving the player their next game task. Unfortunately, for a majority of game developers these sequences have been done with poor cinematic choices, bad timing, staging and animation. Despite the poor craftsmanship, a lot of developers have little room to maneuver due to limited resources left to spare or choices made for optimal gameplay, rightfully so. The player, however, has seen a million movies by the time they see these amateurish sequences. Therefore these sequences are seen as intrusion on gameplay, especially since the control is momentarily suspended. Knowing that we were facing an uphill battle, it was decided to allocate resources early in the project, from engine specs to additional animation staff.

Why go through the trouble of rendering these sequences within the in-game engine rather than pre-render and load as compressed movies? Two reasons: First, we wanted to match the lighting of these scenes with that of the in-game environments housing them. Second, certain elements in these scenes can be altered by Jaks actions prior to sequence start, like broken barrels and crates. And third, we didnt want an extreme visual quality difference between in-game and FMA. We also wanted avoid farming them out to hired guns.

rafei15_lurker_chase.jpg

rafei16_mistyEnemies.jpg

Jak and Daxter's enemies in action and with their props. In the Lurker-chase: Smarter enemies can chase Jak around obstacles and plot new courses as the obstacles are removed.

Art Pipeline

The first step for any background or actors is approved production designs. In-game characters either fit a visual theme to their background or are indigenous to the environments. FMA characters are designed based on their contribution to the story. Front and side schematic, or turns, are then passed onto modelers for construction and rigging. Texture skins are created (using Photoshop) and mapped accordingly, including any alpha maps and environment reflections. Morph targets are created for phonemes, eye brow and mouth expressions for left and right side, usually adding up to 32 sliders, more if necessary. Our primary software for modeling, rigging and animation is Maya. Lightwave is used in parts of morph target construction. An extensive library of proprietary MEL scripts were created to support our specific needs. Voice talents are recorded and passed onto animators.

In-game characters go through the same process with the exception of having few to no morph targets, and any dialogue is treated as voice-over for minimum disruptions to in-game camera. Movement and attacks of in-game characters are first prototyped as much as possible to adjust game design before any animation starts. The enemy animations are further compressed by animating at 15 frames/second, but rendered out at 30f/second.

rafei18_keira.jpgrafei19_maia.jpg

Keira (left), daughter of Samos the Sage, uses her mechanical skills to help Jak and Daxter defeat the brother and sister villains, Gol and Maia (right).

Jak and Daxter was by far the most ambitious project many of us have worked on, but at the end of the day the question for us, and other game developers, shouldnt be how could we get closer to feature animation level quality? (The answer is that we simply need to look at CG milestones and draw from a century of cinema.) The question is how do we come up with innovative ways to give players as much control as possible but still influence the direction of the game? How can we allow them to determine the outcome of their actions without simply going through the scripted steps? How do we create gaming communities that evolve due to individual player actions? Time will tell.

rafei20_jak&daxterVillage.jpg

Visit the village in this typical FMA sequence. One animator would have ownership over the entire scene. The schedule allowed roughly 20 seconds of finished animation per week, per animator. There are about 45 minutes of such sequences in Jak and Daxter.

A NYC graduate of Parsons School of Design, Babak (Bob) Rafei is the art director, character animator and senior visual development artist at Naughty Dog, Inc. Bob was the first artist to join NDI in early 1995 while in the visual development stage of Crash Bandicoot, which paved the way for CB2: Cortex Strikes Back, CB: Warped and Crash Team Racing for Playstation, collectively selling 22 million+ units worldwide. His contribution to this series ranged from modeling and texturing, to character animation and visual development.

During development of Jak and Daxter: The Precursor Legacy for the PS2, Bobs responsibilities included leading visual development as well as contributing to character animations. He is currently doing the same on NDIs next endeavor. He has lectured at the Game Developers Conference on the subject of character design, and has contributed writings to Animation Magazine and Animation World Network (AWN.com).

Tags 
randomness