METAL GEAR SOLID 4 : Guns of the Patriots

By Yoshiyuki Watanabe

XSI Animation

Just the event demo videos in MGS4 are nine hours long. Players can enjoy the longest-ever real-time movie clips used in a game, which are more than three times longer than a Hollywood blockbuster. Even so, some scenes were cut out to maintain the tempo, so the pacing of the video is quite fast.

The team used motion capture for the movement of the characters in the event demos. But for the other motions in the game action, the motion team manually added movements. They focused on how they thought a man of Snake's age should move. Manual animation is also indispensable because of the flexible specification changes that it allows. The total number of motions is 1,700 just for Snake and 4,800 for enemies (such as regular PMC or militia soldiers). And when including the boss characters and facial animation, the total number of motions in the game is about 10,800.

The motion manager, Masahiro Yoshinaga, had the following to say about the superior qualities of the XSI animation environment. "I started out in cell animation, so I like to think about the image frame by frame when adding animation. The animation FCurve is easy to manipulate in XSI, and you can finely control partial motions exactly as you want without destroying the original movement. Also, the high-speed animation playback environment made it easy for us to check the motion before outputting it to the console."

When creating body motions and facial animation, the team needed to create a number of motion variations based on a reference motion. If the reference was a motion pause or facial, they used animation mixer clips so that the expression presettings were saved in a library to make them easier to use. They then imported these presettings, applied the basic facial expressions, and added more detail. Mr. Yoshinaga said that effectively utilizing the animation mixer in this way enabled them to perform efficient work preparations.

During the game action, Snake goes through many different motions such as standing up, bending over and holding a gun. Snake needed to be able to hold a gun during all these movements.

However, creating motion patterns for each of the different gun shapes was not realistic. Instead, first they created motion categories for weapons that had similar shapes, and set information about where the hand held the gun, known as "connect points", to each weapon. Then, the programmers performed a process that aligned the hand positions, which automatically linked the weapons with the motions and made the motions compatible with different weapon variations.

Modeling Size

In MGS4, there are many guns, items and machines that have non-human shapes. The production direction for these machines was performed by Keiichi Umatate.

Texture Setting for General Machines

The shader used for the battle helicopter had basic specular control and incidence parameters. You can see in the render screen the texture structure that was used. From the right, the maps that were applied were defuse, normal, specular, specular gradation and incidence mask. Note that to lessen the image calculation load, the same UV value was shared between them all.

Modeling Using Calibration

Bonneville T100 is a motorcycle made by the illustrious British manufacturer, Triumph. It also appears in the game. To create the data for this motorcycle, the team performed modeling using calibration (image-based modeling).

Mr. Umatate had the following to say about modeling with XSI. "I think that XSI's modeling function is highly compatible with the production process for normal maps, which are essential for next-generation consoles. Often we created a low resolution model and then used the subdivision surface to create a high resolution model. In this process, modeling with XSI was intuitive and efficient.

Thanks to the XSI's non-destructive environment for data, we could perform trial and error operations to improve quality until we were satisfied with the results."

Background Modeling Process

At the beginning of the project, staff from the background group went to various locations both inside and outside Japan to shoot materials. In March 2006 they went to Morocco, in April they went to Peru and in June they went to Prague in the Czech Republic. In Japan, they shot photographs of steelworks and of giant flood containment silos under Tokyo. With these shots, the team wanted to capture the atmosphere and details of their surroundings, but they also wanted to use the photographs as materials and for creating texture. As such, they took over 35,000 photographs.

The background modeling process was as follows. First, the script group in charge of the map design created the rough model data. The data were given to Mineshi Kimura and Yutaka Negishi, who developed realistic data by correcting any parts that were structurally or pictorially inappropriate.
They returned this concept model to the script group, who checked the game balance.
Then, the team performed the actual modeling editing and material setting, and set the collision information. This brought the data close to completion.

The team did not use LOD for the background data. They made partial use of LOD only for large volumes of trees or grass. 150,000 to 200,000 polygons were imported into the PS3 in each load. If the data exceeded 200,000, they were divided into separate loads.

Even when a low number of objects was expected in a scene, sometimes there were more than 5,000 objects, and sometimes the number approached 10,000. The team used XSI's NetView to manage such large numbers of objects. First, they created a management page for a small object list. Small objects registered on this page, such as bottles, frames and potted plants, could be easily positioned just by dragging and dropping them to the XSI background data.

A wide variety of attribute information was set for the objects that appear in the game. For example, objects for when guns are shot, sound effects when something is hit, physical properties, and OctoCamo information (changes that camouflage Snake's suit as he creeps alongside a wall). These attributes were easy to define on XSI by giving them names. The team added a Null inside the object node and then set the name, such as IRON_*** or WOOD_***. When these data were output to the game, the various reactions that were specified by the attribute information were shown.

　
Example of OctoCamo changes

The team performed the advance baking of apex colors and light maps with XSI's render map. In general, they used Final Gathering to bake rough shading into the apex color. However, in the case of light maps, after significantly compressing the texture volume, this technique is not required in areas where the shadow buffer is active. The shadow buffer can be used much more in the PS3 than in previous consoles, so the background shadows and character shadows can co-exist in a non-destructive way. For this reason, in most cases real-time processing is used for shadows.

But in the shade, the normal map is less effective than in sunny areas. Another issue is that second and third order light expressions are also required, which the shadow buffer cannot keep up with. In response, the team set data known as LSC data to supplement the lighting texture. LSC data stores light positions and brightness information in an external file, which can then be used on the console. They performed the lighting settings by importing the background created with XSI into a lighting editor, an in-house tool that displays a preview that is almost the same as the image on the console. After adding colors and accents in a way similar to painting, they could perform a rough preview even while in the OpenGL condition. They could also perform quick and accurate previews on the console by compiling from the lighting editor.

In addition to lighting for these background models, the team also performed lighting for the characters. They set the point light sources and environmental lights to suit the atmosphere and colors of the background. After finishing this, the final job was to perform the settings for the OctoCamo. The game is notable for how the light intensity changes in different situations, such as for camouflage, in direct sun, in the shade and when light bulbs are broken.

Work screen in the lighting editor

Comparison of lighting effects on a character
Before lighting		After lighting

Role of Programmers

Most of the programmers in MGS4 performed programming work related to game processing, while at the same time developing in-house tools to support production. They developed a wide variety of tools to make work easier for the designers. These tools include the previously mentioned lighting editor, a preview environment with the same quality as the console, and their own particle engine and particle editor. Kunio Takabe explained that turning the environments, expressions and request items that the designers ask for into reality is an important role for the programmers. This means that good communication and mutual understanding is very important.
Effects used in the game, such as depth of field, dust clouds, snow and camera blur, were also developed by the programmers. The team performed actual lens simulations for the fuzziness in the depth of field to accurately calculate the focal length, angle of view and F value. But in some scenes, if the accuracy was too good it created problems in the display. In such cases they used the old depth of field effect, which designers have used for many years to control the fuzziness.

Without camera blur effect		With camera blur effect

Without depth of field effect		With depth of field effect

Since this project was for the next-generation console, a programmer dedicated to real-time shader production was also attached to the team. They used a real-time shader based on the cg language, because it can be used in both PS3 and XSI. The real-time shader work was started after the programmers submitted the basic shader. The team added functions and variations as required. By the end of the project they had developed over 150 different shaders, for characters, background and machines. For example, a derived shader was developed for expressing dirt (such as mud, blood or water) on a body. Further, by finely controlling dirt in apex units, the team achieved highly realistic expressions. A derived shader was also developed for Snake's OctoCamo, which was described earlier.

	The simplest shader construction with a relatively light processing load. Only base color and normal textures are used. In addition, apex colors are used within the shader.
	A shader construction with quite a lot of functions and a heavy processing load.Because layers can be used, a second normal map called the subnormal can be used in combination with the first. It is a multifunctional shader that can also apply cube maps. The textures that are used are the base color, layers, normal, subnormal and specular.

　
Real-time shaders that were set for machines and characters

In real-time shader development, one problem was expressing water and the sea. The team developed seven or eight shaders just for water through a process of trial and error. These included shaders for murky water, swirling water and transparent water. Real-time shaders were also used for debugging. For example, by assigning a special shader, they could check in a preview whether any tangent baking had been forgotten.

Finally

Starting with Hideo Kojima himself, the MGS team directors perform strict quality checks. They make no compromises. For example, during production they made four changes just to Snake's face. Of course, since this was performed not in pre-rendering but in real-time processing, there was a risk that specification changes could impact the game system itself. But every team member was determined to raise quality with as many improvements as were possible in terms of time and technology.
Yuji Korekado, the program unit manager, described how they work together. "Instead of creating things systematically, Kojima Productions is more like a gathering of craftsmen who are dedicated to their work. Of course, we use a whole variety of techniques to produce better products, but in the final analysis, we produce our best results when the spirit and courage of our team members come together."

Of course, gamers have a very high expectation of the Metal Gear Solid series, which is so popular all over the world. All the team members knew it was their mission to produce a superb product and could feel the pressure to take the game to the next level. But everyone, both at Konami and at their partner companies, was very enthusiastic about MGS and highly motivated right up to the end of production. It was this that made the project such a success.

Looking back over the project, Mr. Negishi gave us the following final words. "All MGS4 staff members are confident that this is an excellent game that they can send out with pride to fans around the world. I think that being blessed with such an excellent staff was the most important factor in the project's success. But I also think that choosing XSI for the development of this next-generation title, which involves such high quality images and large data sizes, may have been a factor in our success. The flexible and robust XSI architecture, which supports as many quality improvements as time allows, is really wonderful. Useful functions such as Gator and the superior animation editing environment also significantly reduced the amount of work required in development."

The Kojima Productions team that we interviewed

The team at Kojima Productions, Konami Digital Entertainment

Yutaka Negishi, Design Unit Manager
Yoji Shinkawa, Art Direction Manager
Keiichi Umatate, Gun, Item and Machine Production Manager
Hideki Sasaki, Character Facial Setup Manager

Masahiro Yoshinaga, Motion Manager

Mineshi Kimura, Background Production Manager
Takahiro Omori, 2D Production Manager
Masaya Kobayashi, Event Demo Manager
Kunio Takabe, Program Unit Technical Director
Yuji Korekado, Program Unit Manager

Click here for a video that describes the XSI functions.

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