Tuesday, March 20, 2007

VFX and Narrative Cinema

Kristin Thompson has written a thoughtful piece on the Bordwell Blog, one of the very few film criticism sites worth reading, on the role that digital visual effects can play in affecting the narrative of cinema. The default position of many critics seems to be that computer generated visual effects (CG VFX) exist to produce spectacle alone, sometimes at the expense of all else. The article, a review of a book by Shilo T McClean, discusses the idea of different types of CG VFX from the documentary (reconstructing that which no longer exists, Rome or a dinosaur for example), the fantastical (Lord of the Rings) to the seamless (e.g. sky replacements). These are interesting distinctions but I think they all share a rather vital point not mentioned in the article and that is, regardless of whatever type of effect is being achieved, they are hyper-realist not photo-realist in nature and this, I believe, is the defining feature of modern VFX which sets it apart from almost all that has gone before. Let me try and illustrate with a practical example of a single shot from a show I worked on and therefore know intimately.



The main pull-out reveal shot of the Greek armada in Troy starts on a real ship, built for the film, and pulls out by means of a helicopter to a distance of a mile showing the whole fleet (some 600 ships or so, all digital). The original photographed plate runs to over a minute in duration. A photo-realistic approach would be to accurately match the angle of the sunlight as it was when photographed along with any atmospheric conditions on the digital ships and then composite these into the photographed plate. This is not what happened. The actual creative process followed was hyper-realist much in the manner that the hyper-realist painters of the 1970s, Charles Bell or Richard Estes took reference from photographs but altered them to create a more aesthetically pleasing, albeit totally believable final result.

For the Troy shot we changed the angle of the sun as it played upon the digital boats to give them a more interesting look and to allow us to see the digital crews milling about on the decks. We added wakes to the boats, including the real one, in spite of the fact that Greek penteconters are keel-less and of shallow draught and therefore create almost no wake. Audiences expect to see a wake on a boat and we cannot disappoint them even though it is not "real". The plate as photographed was very misty. This was deemed unsuitable as much of the fleet would be lost in the fog. Instead a matte painting showing a stormy sky was added to enhance the aggressive and brooding mood of the shot. The sea was darkened and made more contrasty for the same reason. Photographic reality is subverted at every turn to suit the needs of the story and to create a stronger image. To add the final extra impact that the visual narrative required at this point in the film the photographed plate was re-timed so that the footage gradually sped up as the helicopter pulled away. If you were to watch the real crew on the real boat you could see their movements speed up as the shot runs. The increased speed is added seamlessly so the audience is unaware of the deception, the CG crews remain at a normal speed and the drama of the camera move is accentuated. I hope this demonstrates that one of the fundamental changes that CG VFX has brought is the idea that the entirety of the film is plastic, both spatially and temporally. The Troy shot features changes within the frame of geometry, of lighting, and it is changed temporally to allow the precise timing that cuts best with the subsequent shots. Even the real elements of the shot, such as the fog, are changed where it is deemed artistically necessary. The photographed plate becomes merely a guide, a sketch of what is wanted and the visual effects artists render the finished result.

The book Thompson is reviewing makes use of a film count of movies featured in Cinefex magazine to determine whether the suggestion that CG VFX are mostly deployed in science fiction and horror films and are thus tools of a certain genre is correct. Her research suggests not but I have to take issue with her logic in assuming that the films featured in Cinefex are those whose effects are regarded as being most significant. This is often not the case. Cinefex is run by a very small team. In order to write a piece they need access to the supervisors on a project, they need interesting photographs to illustrate the article (nerds sitting in front of workstations are not deemed to cut it in spite of the fact that this is how VFX is mostly practiced these days) and they love a show where miniatures or animatronics are used because these are photographable and understandable by the audience of movie geeks who reads Cinefex. Computer Graphics is very technical by nature and without extensive background reading in a variety of disciplines even the most basic techniques can be baffling to the layman. Everyone understands a model or robot conceptually however. Cinefex is not regarded highly by visual effects practitioners for these reasons and many films are featured often because the supervisor is very amenable to interview and speaks well or because there is a pretty miniature shoot that can be photographed. Cinefex must be seen in the context of those for whom it is written, the film geek, not the visual effects artist. As such its choice of subjects cannot be assumed to be the most significant films made.

The final point I would like to address is the timescale of CG VFX within the whole production. Obviously VFX are completed after the film shoot wraps but what is perhaps not so well understood is that generally the process begins before photography commences, often long before. The pre-visualisation process (pe-viz) has become a staple part of VFX heavy film production, of whatever genre, as a vital step between the story-board and the actual shoot. In pre-viz low quality models of all the elements that will make up the final shot, whether ultimately real or CG are built and roughly animated to block out their movement and that of the camera. The sequence is put together so that the director, producer and effects facility can see that a sequence will work before a foot of film is exposed. In many cases the freedom of the pre-viz team to lay out the sequence means that in a cutting, and camera-operating sense they take over from their real counterparts. The director will ask the DP to match what was produced in the pre-viz. This is not always the case but it does demonstrate that CG VFX can play a dramatic role in the construction of the filmed narrative and that, like it or not, it is all pervasive in mainstream cinema, and increasingly common in alternative cinema. The flexibility it offers to determine the flow and staging of the film ahead of the shoot and the ultimate control it offers to manipulate the filmed elements in post-production is simply too powerful an option for film-makers to ignore regardless of genre, budget or style.

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