Thursday, October 11, 2012

Two VFX Examples From The Bourne Identity (2002)

This post will showcase two very elegant visual effects shots/sequences in the movie The Bourne Identity (2002).

Sadly none of the case studies today feature giant robots or things that explode loudly.   This is because of the filmmakers' failure to understand that giant robots and exploding things seasoned with an occasional space battle or cute furry aliens are the most important elements when crafting a significant visual effects project.  Instead what we have here is an odd little film with a few likable characters and a lot of violence, but very few explosions.  Even so, we can use this project as a modest example of how visual effects can improve a film or lower the cost of shooting something without an explosion per se.

There is a well-known aphorism from film editing that goes something like "Good film editing should not be noticed by the audience."  The editing should be subliminal, you should not (consciously) notice it.  In a similar way, if the audience thinks "wow, what a great visual effect!" that is not the desired result. They should think it is real.  Of course there has to be some level of suspension of disbelief for that to work in many cases when, for example, one is showing a giant robot eating an alien world or some other subject not drawn from day-to-day experience.

But in the case of a film that takes place in a contemporary setting and in which there are not overtly fantastical elements, then hopefully the viewer will just be involved in watching the film and not think that he or she has just witnessed a visual effect. There are some surprisingly effective and useful visual effects that are completely unnoticable unless someone points them out to you.

To illustrate this, I am going to showcase, as best I can, two shots/sequences from the first Bourne movie: The Bourne Identity (2002). I think that both of these sequences work very well and both of them are implemented in a remarkably simple manner.   In both cases, digital technology made the shots easier to execute.  In the second case, the shot could not have been done without a digital technique.

Sequence 1: The train at night

In this sequence, Jason Bourne, who is suffering from amnesia and does not know who he is, has very little money, is travelling on a train from France to Switzerland.

The shots break down as follows (times are approximate):

1. A five second shot of a modern train going into a tunnel,
2. A twelve second shot with a slowly moving camera of Bourne looking out a window of a train, either looking at the tunnel moving outside the window or at his own reflection,
3. A three second shot of Bourne's hand fiddling with a plot device,
4. A thirteen second shot of Bourne at his destination outside the train looking lost.

One of the unusual things about this sequence is that it moves very slowly.  In general, we do not like people to have the time to study the effect, as they can usually see through it if we give them more than a few seconds.  But in this case, we stare right at the effect for 12 seconds and it works fine.

In the second shot, the one with the moving camera, the original element was shot in a train that was not moving, with the window blacked out (the reflection of his face and seat are there, but it is black otherwise with no sensation of movement). There is a light on the set illuminating Bourne's face intermittantly to simulate the idea that the train is passing something that is giving off light, such as a signal, but there was nothing beyond the window but black in the principle photography.  The camera was tracked in 3D using some early tracking software and a 3D element of some abstract, dark, tunnel-like textures rendered moving past the camera at high speed (e.g. with a lot of motion blur) and rendered with the tracking camera move. This was then composited against the original shot using a simple hold out matte generated of the outline of the window. The element was basically just overlayed on top of the shot in the area of the window, you did not mind that the textures were visible "under" the reflection of Bourne.

The end result of this is that you completely buy that Bourne is on a train moving at night. One 3D track, one simple 3D element, one travelling hold out matte, and a simple additive composite within the hold out area. I think it works perfectly and it was very inexpensive to execute.  Without it, I don't think the sequence would have been as believable (in other words, had Bourne been looking at his reflection against a black background without any sensation of motion). Had it been shot in reality, e.g. a train moving at night, it would have been much more expensive.

Alternatively, one could have used rear projection to do a similar shot, but you would not have been able to move the camera that far off axis in a rear projection situation.   One could have done a similar shot with a moving camera and traditional techniques, I think, but it would have been more difficult.  Using traditional techniques, I would have shot the principle photography using a motion control or motion tracked camera and then reused that move to control a motion control camera to shoot additional elements, in particular to  rephotograph rear projection art work which had previously been created with a suitable blur of movement (for the movement of the train past the window, not the movement of the camera).   Either I would have shot blue/green screen outside the window of the train in the principle photography, or if I was using motion control to shoot the plate, repeated the movement with a green screen in order to get a hold out of the window.  Then I would have optically composited and it all would have worked.  Here the digital techniques really do make this shot straightforward, however, and less costly to execute.

Here is the sequence online.

Sequence 2: The incident in the park

After Bourne arrives in Zurich, we have one establishing shot of him alone, at night, in Zurich with snow falling which is about 7 seconds long. We cut to Bourne sleeping in the snow on a bench. Two police officers wake him up, ask to see his ID, and tell him he can not sleep there. One of them gestures with his nightstick, and Jason grabs it. The two police officers are standing above him, he is sitting on the bench, unarmed.

The next six or seven shots (depending on how you count) are each very short and appear almost continuous, even though they are not.   In these shots,  Jason disarms both men and knocks them both unconscious as well as taking one of the police officers revolver.  When he is done, Bourne stands puzzled over the two unconscious men and seems to wonder what happened.

It looks completely natural and Jason does not even appear to be working very hard.

It reminded me, as it was intended to, of when I have watched a dancer or gymnast perform: it looks as if what they are doing is easy even though you realize that what they are doing is impossible.

What they did is as follows. First, a martial artist working for the production choreographed the actions of Bourne and the two officers moving very slowly. As shot, the actors moved at a comfortable speed and did not try to maintain a constant rate.  The camera changes position during the shot so presumably it was shot several times from different positions.   You will also notice that Jason appears to move in what seems like clean, deliberate motions with brief pauses between them. The speed of the performers was not constant, to get the effect of the police officer on the right being knocked to the ground, for example, the (presumably) stand in had to basically throw himself onto the snow so it would react properly.  

Then the effects supervisor, Peter Donen,  took the shot(s) and digitally retimed them, varying the apparent speed continuously through the shot(s). There is also some very good film editing going on.  The sequence that results looks flawless to me, and as I have mentioned, almost appears continuous, even though in actuality there are several cuts.  In this case, digital retiming which makes use of a variety of image processing technologies involving motion analysis (image flow) between frames enabled this approach.  Previous to this digital technique, the traditional techniques could do retiming but only in specific increments of the frame rate, e.g. one could skip frames and double the speed of the shot, but that would not have been sufficiently flexible and continuous (e.g. moving at fractional speeds).  Keep in mind also that this retiming technique could only work in this situation as long as one keeps to very short cuts because we have snow falling.  Assuming that this is real snow (and it very well might be, or practical snow on the set) then it will appear to change speed if we do retiming on longer sequences and just allow that to be viewed.  So this technique has to be used in very short segments or elements like the snow have to be added later.

Here is the sequence online.

So here we have two examples of visual effects used to serve the story that were both elegant and inexpensive to do. The second sequence is an example of making something that is inherently fantastical look natural and realistic.  We can forgive the lack of a cute furry alien or a giant robot since the filmmakers have executed their inferior robot-less vision with such skill. 

The effects supervisor and my friend, Peter Donen, passed away about four years after these sequences were done, tragically of a heart attack in his mid-50s. What was especially sad was that his career was just taking off after decades of struggle. He had the misfortune of being the son of a very famous man, the director Stanley Donen.

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