Softimage|XSI publish PS3 GAME METAL GEAR SOLID 4 Character Production Workflow

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Forum: CG News
Posted By: lostxian
Post Time: 09-22-2008 at 07:08 AM
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Character Production Workflow

from: http://www.softimage.com/

Most of the characters that are animated on the console, including the main character, Snake, have been restricted to a data size (including the face model) of about 5,000 to 10,000 polygons. Further, characters are used that have the same polygon resolution in both the game action and the event demos. This means that the game screens and video clips are seamlessly connected, making it easier for players to become emotionally involved.

As mentioned above, with the exception of crowds, characters are used that have the same polygon resolution in both the game action and the event demos. Separate from the resolution model used on the console, high resolution data are also simultaneously modeled for generating the normal map. Details such as creases on clothes are then expressed with the normal map that was generated from the high-res model.

In terms of bones used for constructing the bodies of characters, about 21 joint bones were used that contained animation data and were activated through these data. But many auxiliary bones were also used to supplement movements such as the twisting of knees, elbows, legs and arms. These were not activated by animation data. Rather, they were linked to the values of the basic joints that were activated by animation.

The team used these specifications not only on XSI, but also on the console. They could perform the same control on the console simply by outputting an auxiliary bone definition file from XSI.

Because the auxiliary bones themselves do not contain motion data, the data size can be kept to a low level. Further, if auxiliary bones need to be added or deleted, the operation can be performed simply by changing the model data without having to reconvert the motion data.

Amazing Facial Animation



One of the main features of MGS4 is its world-class facial animation. How did the team create such realistic facial expressions? Because lip synch work is performed in the localization stage, and to lessen work loads, audio analysis animation is used in the Metal Gear Solid series. For example, in MGS4, lip synching in the English & Japanese versions was performed using different types of audio analysis software. Emotions & facial expressions other than lip synching were added through manual animation. In most cases, facial expressions and phoneme elements do not interfere with each other, so both can be worked on in parallel.

It was this that allowed the simultaneous worldwide release of the title. When performing audio analysis, the facial expression components (such as anger or laughter) and the phoneme components in each language must be divided into separate parameters. These must then be reproduced as rig behavior. Although it is possible to create parameters for bone rotation and movement, the team said that this would make the rig too complicated and make it too difficult to predict bone changes as an envelope. In other words, there would have been two problems had they tried to perform facial animation using bone control only: it would have been difficult for the designer to perform intuitive operations, and difficult to create facial expression and phoneme parameters for bone behavior.

On the other hand, while shape animation has the disadvantage of producing linear interpolation animation, it is very easy to create parameters for phonemes and facial
expressions. But perhaps its most important benefit is that the designer can intuitively predict the results.

For these reasons, the team based the rigs in this project on parameters created with shapes, outputting the results as bone animation.

This setup allowed animation automation using audio analysis (automated animation was performed not just for the mouth, but also the tongue and throat) to coexist with a rich range of character emotions that were added manually. In the Flash movie below, you can see how smooth muscle movement is reproduced using a top-quality rig setup.

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