Postcard from GDC 2005: Real-time 3D Movies in Resident Evil 4

One of the final lectures on Thursday was from Yoshiaki Hirabayashi, lead designer on Capcom's Resident Evil 4 . One of many distinctions in this game over previous entries in the series is an absence of prerendered cutscenes; any cutscenes present are rendered in-engine, and sometimes include QTE segments (as popularized in Shenmue ). At other times, the player must tap the Action button to make Leon run faster. Overall, the experience is a more dynamic one than in the past.

The reason for this, Hirabayashi said, speaking quickly through translation, is that he feels a videogame is a package as a whole; although pre-rendered movies are pretty, they passive, and pull the player out of the game. At least real-time movies are not as distracting, as the game remains consistent. Furthermore, when you change things during development, it often means you have to go back and re-render your cinematics to match again; this takes time and resources that could be better used elsewhere. Real-time cinematics remove that problem.

The normal structure in past Resident Evil games, Hirabayashi showed, was as such: (game)(movie)(game)(movie). The movie portions existed in part to give the player a rest, and allow a release of tension. However, Hirabayashi did not like forcing the player to take a break; the use of the action button in RE4 is an attempt to involve the player again. "If the player does not have to touch the controls," Hirabayashi pointed out, "he might get up and go to the bathroom. That is not ideal."

With this added focus on real-time cinematics, Hirabayashi feels that improving the quality of the cut-scenes increases the quality of the game overall. One of the important ways to involve the player is to trade off realism for subjective impact. "We have to make things feel real, not look real." Hirabayashi feels that making the characters "more appealing" than in previous games is the other big issue. The problem, of course, is what it means to be appealing. He asked series producer Shinji Mikami for advice; what Mikami told him was to make sure characters' expressions were always appropriate to their emotions, and to make sure the characters move and behave in ways appropriate to their personalities. Use animation to show character. Hirabayashi chose to take this a step further, and ensure that every character has a slightly different expression in every shot.

Using one of the lead females as an example, Hirabayashi said she has thirty-six targets for her facial animation: five times more than in past games. One problem is how much memory it took to hold so many high-resolution models in memory; what they did is break her expressions into two banks; one with the twenty-four most standard targets, and a second slot that contains any five of the remaining targets, depending on the demands of the scene in question.

Every character also has three resolutions of model and three texture qualities; these can mix and match, depending on what a scene will allow the team to get away with. Darker lighting will allow them to use a lower quality of texture, for instance, while bright lighting might require a high quality of texture yet let them drop the polygon count. As an aspect of this, characters use different textures for their pupils in different lighting situations.

A new technique they played with for this game was "projection lighting," which works kind of like colored lighting, except a texture is applied to the light source, causing that texture to radiate out onto whatever the light touches. Hirabayashi showed a scene between Leon and Wesker, both with and without skylight shadows projected onto them; the scene with the shadows was much moodier, and the models were less obviously "false"-looking.

One other new idea was real-time rendered textures: Hirabayashi showed a scene where Leon notices the President's daughter on a TV monitor, as a townsperson is about to attack her. The way this works is, the action on the screen is actually happening somewhere nearby; they just drop an extra camera on it. The data from that camera is then cached and downsampled, to use as a texture.

In producing Resident Evil 4 , Hirabayashi's team took a new approach to workload management; in the past, they relied on the programmer to implement pretty much everything. For this game, they set up a web server with an XML-based data management system on it; in effect, this allowed everyone - all of the team members -- to work at once. It was something of a revelation; there were no more traffic jams, there was far less pressure on the programmers. This development also means that the designer has more control over implementation; he can solve problems by himself, without relying on the programmers. Beyond this, it helped organization and general keeping track of resources.. If data is missing, if a particular scene needs a texture that hasn't been delivered, you can see it right in front of you.

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