When digital revolutionizes special effects in cinema

Who, from the worm of the sands of Dunesexplosive cascades of Dying can wait or cobwebs Spiderman, will win the 2022 Oscar for Best Visual Effects on Sunday, March 27? One thing is certain: whoever wins, digital special effects will remain in the spotlight.

The Academy of Oscars has been awarding this prize since 1939, long before the era of the pixel. With the cinema, the tricks of the theater and those of photography come together. Fashion takes thanks to the filmmaker and illusionist Georges Méliès (1861-1938), at the turn of the XXand century. Then for decades, the matte painting (“painting on cache”) takes center stage. It involves painting a set or a set element on a glass plate, which is filmed at the same time as the scene. An alien ship in the sky? A painting.

Loaded with sensors

The techniques evolve, we start to use a filmed decor. Chases and sea crossings are embodied in the studio while in the background, videos of highways or raging waves are projected. Problem : “The spectacular decor is of poor quality because it was filmed, projected and then filmed again”describes Jean-Baptiste Massuet, lecturer at Rennes 2 University and historian of digital technologies in cinema.

→ PORTRAIT. The great illusion of Georges Méliès

Despite some improvements, the real “solution” comes with green screens and post-production keying. Instead of filming the chase at the same time as the shot of the highway broadcast behind, it is filmed in front of a green screen which is then replaced by a filmed shot or by a digital creation from scratch. “CGIs have been around since the 1970s and film Worldwest (Michael Crichton, 1973)who used it to simulate the point of view of a robot »recalls Réjane Hamus-Vallée, sociologist at the University of Évry-Val-d’Essonne and specialist in special effects. “But the technique really took off in the 1990s with Jurassic Park (Steven Spielberg, 1993). »

Progress does not stop at the decorations. The actors themselves find themselves in tight lycra, clad in sensors. “Motion capture” and « performance capture ”, two equivalent techniques, allow them to be digitally transformed into werewolves or hobbits (the characters imagined by JRR Tolkien). “It is easier to apply a prosthesis or make-uprecognizes the expert. But digital post-production makes it possible to add blood effects to a wound as well as to erase wrinkles, which will never be possible with make-up. »

Scenes filmed in a cylinder 22 meters in diameter

With more or less success. The failure of the recent film Cats (Tom Hooper, 2019), with humans disguised as cats, is a good reminder that digital sometimes makes monstrous what theater make-up makes acceptable. At this game, “it is better to assume totally different and imaginary creatures”, estimates the specialist Jean-Baptiste Massuet. Credibility also goes through the addition of faults, such as the “motion blur” (motion blur).“Adding blur between images paradoxically makes the movement of a digital creature more realistic”details the specialist.

Long a major consumer of green funds with its superhero sagas, Disney decided, in 2019, to return to basics, or almost. No more long and meticulous overlay, everything is displayed at the same time as the scene is shot on set. Built by the company Industrial Light & Magic, the decor is digital and scalable, thanks to the combination of two tools: video game software, such as the Unreal Engine, which generates universes more real than life, and walls of LED screens (Light-Emiting Diode, light-emitting diode screen), which display these universes.

For the series The Mandalorian (Jon Favreau, 2019), the majority of the scenes were thus shot in a cylinder 22 meters in diameter. With the exception of the floor, everything was just successive screens that displayed the desired decor. The actors evolve in the middle of this enclosure, while a position sensor is placed on the camera on set. With each movement of it, with each zoom, the Unreal Engine generates the corresponding view, and the LED screens display it.

“The corridors where the battle scenes are played out only exist digitally”says Pascal Pinteau, screenwriter and author ofSpecial effects, two centuries of history (Bragelonne, 2015). “They were modeled and then displayed on the LED walls. And when the director decides to lower the camera to film at boot height, the display adapts instantly. It’s amazing, the viewer does not realize what is displayed and what is true, ” he specifies.

“Know how far to go”

Main constraint: the entire 3D set and special effects must be designed before filming, so that the computer can perform display calculations instantly, as the camera moves. In exchange, all post-production disappears or almost. “With this system, called ‘StageCraft’, 90% of the scenes filmed could be used directly to The Mandalorian »figures the expert, who foresees increased use of this technique in the coming years.

→ CHRONICLE. Cinema: sensory dark rooms

By immediately and permanently providing the right environment, the system avoids the problem of light and reflections. The shadows on the metal armor of the intergalactic bounty hunter match the sets exactly. “With a green background, the reflection can leave a greenish color on a white dress, for example, which is then difficult to remove in post-production.describes Pascal Pinteau. There, this problem does not exist. The light is always the right one, and you can shoot a twilight for five hours! » No more depressed actors playing in front of a big nothing. No need to imagine the grandiose citadel or the murderous explosion, everything is displayed in real time.

Whether these digital effects will age well in the eyes of the viewer remains to be seen. “Our gaze gets used to the codes of the timesJudge Jean-Baptiste Massuet. With each evolution, the previous one seems dated. » Still, some scenes made using models or costumes stand the test of time better. “The viewer is much more tolerant of reality, models and animatronics (robotic puppets, Ed), slice Réjane Hamus-Vallée. It is all the director’s talent to know how far to go and to choose the best technique for such and such a scene. » The computer is not everything.


Special or visual effects?

SFX. The abbreviation of Special Effectswhich would be translated as “special effects”, refers to the tangible special effects produced on the film set, such as make-up, prosthetics, animatronics (animated creatures).

VFX. The abbreviation of Visual Effects (“visual effects”) refers to effects added digitally, by computer, most often in post-production. It is for example the replacement of the green background by another image.


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