I am not fond of CGI. It has gone from helping filmmakers tell their story to invading cinema with its sterile, implausible fakery. For the avoidance of doubt, by CGI I mean images that are created ex novo with a computer, not the compositing of multiple layers to create the illusion of a seamless scene.
“You only notice bad CGI”
That is self-evidently true. I take no issue with CGI that blends effectively with the live action; I have it in for certain cases of CGI that ruin the film experience. Specifically:
(i) shots that would have been done more convincingly with practical effects for a similar cost;
(ii) CGI that gets the texture completely wrong. In such cases I don’t care if CGI was the only viable way to get the concept on the screen. If it looks like a video game, I count it as a cinematic failure and that’s that;
(iii) shots of large creatures or objects that move in ways that are not consistent with the fundamental laws of physics. More about this below.
The first problem I have with CGI is its texture, which often fails to match the scene in which it is embedded or does not match the real-life characteristics of whatever it is attempting to reproduce. CGI often looks electronic, ugly and fake.
Smoke and fire, for example, appear to be difficult to render convincingly in CGI, despite — or perhaps because of — the reliance on mathematical models, yet every film with smoke or fire in it resorts to this toxic shortcut. I am well aware of the fact that CGI saves the hassle of dealing with real fire and smoke, but if those images fail to convince, it’s just not good enough. It is somewhat pathetic that smoke is less convincing in modern movies than in those made 50 years ago.
CGI defies the laws of physics
The other trait of CGI that inhibits the suspension of disbelief is that large CGI creatures generally do not accelerate or decelerate in a manner consistent with the classical laws of motion. Newton’s Second Law of Motion states that the acceleration of a body is proportional to the force acting upon it and inversely proportional to its mass (F = ma). In simple terms, for a given force, more massive objects will speed up or slow down more slowly than less massive ones.
This is not about academic pedantry: even those who have no knowledge of physics understand intuitively that a 30-foot robot made of solid metal cannot possibly move with the agility of a 6-foot human, because to do so would require a force that cannot reasonably be exerted by it within the bounds of a plausible power-to-weight ratio. Larger creatures have a lower power-to-weight ratio as a direct result of the square-cube law (weight grows as the cube of linear dimensions, whereas strength only grows as the square of linear dimensions, so the power:weight ratio declines with increasing body size). This is why massive yet agile robots look so implausible that they are more like anime cartoons than cinema.
High-end practical effects age better
Well executed practical effects are entirely convincing and therefore future-proof. One of the finest examples is the Queen Alien in James Cameron’s Aliens. It was a 14-foot puppet that was held up by a crane and had two stuntmen inside the Queen’s chest to move its four arms. The beautiful puppet was designed by Cameron and made by the brilliant Stan Winston. As a practical puppet that was manoeuvred by a crane and stuntmen, the whole rig was fully subject to the laws of physics – there were no incongruously agile movements.
The natural movements, smoke, dark fill / hot backlight combination and liberal application of slime all contributed to the illusion of a living creature. To this day, the scene is wholly convincing and a prime example of directorial genius at work.
Another example of a masterfully executed scene that nowadays would be liberally splattered with CGI is the opening scene of Ridley Scott’s Blade Runner. That majestically dystopian cityscape was created in-camera with practical models, matte paintings and real fireballs. The result is that this scene remains one of the most mesmerising and convincing in the history of cinema. It will look just as real a century from now.
A final example is the filming of the helicopter chase in Mission Impossible: Fallout. Tom Cruise went to the considerable effort of learning how to fly helicopters and execute the dangerous corkscrew dive so that the scenes could be shot in-camera without CGI. They even constructed special camera rigs to place the camera outside the helicopter’s cockpit, affording a clear view of Tom Cruise as the pilot. The result is beautiful. As good as CGI can sometimes be, you just can’t beat reality. I have major respect for Tom Cruise!
James Cameron does it well
I am not arguing for the wholesale abandonment of CGI. It most definitely has a role in film production. It tends to work well when two conditions are fulfilled: (i) it is used only when it offers the most convincing solution to the scene’s requirements, and (ii) it is blended convincingly with the live action. James Cameron is the director who has used CGI most convincingly – from the water tentacle in The Abyss to the wide shots of the Titanic populated with CGI passengers, he knows how to use enough CGI to solve creative problems without spoiling the look of the film with digital artifice. There are numerous examples of CGI in his films that go unnoticed precisely because he blends them with practical effects so well. He is a wily director who is careful not to use the same trick more than once in a scene snippet, as he stated in his Aliens DVD commentary.
Some stories can only be told with CGI
It is self-evident that some films can only be made with extensive use of CGI. The Transformers films are an obvious example. This does not mean that they can get away with the physical motion incongruities described earlier. Gollum is another creature that almost pulled it off. When I see it, I marvel at the CGI work they did instead of marvelling at how real it looks – a subtle but important difference.
They don’t make them like they used to!
Nostalgics often lament how things are no longer made as well as they used to be. This is true across most industries. It’s the classic dynamic: a product is initially developed and produced to a high standard. Customers love it. Then competition sets in, profitability declines and production costs need to be cut, so they devise a way to make a product that looks the same and performs similarly but is in fact of lower quality.
This is, in effect, what has happened with films. Sweeping crowd scenes that could be shot with real extras are done with CGI instead because it saves money. Traffic jams that would have required dozens of cars and drivers are similarly conjured with strings of 1s and 0s. The result is just about good enough to project on a big screen, so they get away with it.
36 years ago Ridley Scott treated us to gorgeous cityscapes painstakingly assembled by a master director. Now they fob us off with lifeless, gratingly artifical panoramas made entirely with computers. I can’t wait for this dark age of cinema to run its course.