What is Computer Generated Imagery (CGI) and what is it used for?
It is the application of the field of computer graphics, specifically saying, the use of 3D computer graphics to special effects in movies, printed and electronic media. CGI is used for visual effects because the quality is often higher and effects are more controllable than other similar methods. Some examples include constructing miniatures for effects shots or hiring extras for crowd scenes. It allows the creation of images that would not be easy to be created using any other technology.
What is a Cyberpunk movie?
Cyberpunk movie is a genre of Science fiction movies which uses cybernetic techniques and focuses more on the high-techs used in a futuristic setting. Origin of this Cyberpunk movie can be traced back to the 1960s and the 1970s. Cyberpunk is often set in urbanized, artificial landscapes, and “city lights, receding” was used by Gibson as one of the genre’s first metaphors for cyberspace and virtual reality. Recently released Blade Runner 2049, Upgrade (2018) and the Netflix’s TV series, Altered Carbon, all belong to this category of genre.
What are the CGI Techniques used in Alita: Battle Angel?
In this movie, the visual effects are focused mostly in recreating Rosa Salazar’s eyes and body into the 3D eyes and cyborg body of Alita.
CGI eyes used to be purely computer generated, but now, VFX designers can manipulate an actors’ eyes to create the ones we see onscreen. In 2016, a team of researchers used a database of images of eyes to mimic the “perfect imperfections” of the human eye’s design, using facial scanning for eye reconstruction. The WETA simulation creates geometry for each layer of the eye, then breaks up the eye’s fibers and stretches them, in a process similar to what happens when eyes age. Gollum’s eyes from “Lord of the Rings” used 50,000 digital polygons. Alita’s, by contrast, have 9 million polygons in just one iris. Alita’s two eyes went through approximately 50 variations over several months, during which the designers made a series of tiny adjustments: to the corners of the eyes, the outsides of the eyes where the eyelashes come together, arranging each individual eyelash, and to how the eyes’ movements were reflected on the character’s forehead and in her body movements. The next challenge was mastering how light is reflected in the eyes and then, even harder were the tears.
From digital lighting and an improved ability to simulate facial musculature and skin it was all important to include Rosa Salazar’s performance into Alita’s Computer-Generated body.
The war being raged throughout Alita: Battle Angel is one that which is a matter of technical intervention. In the world of CG imagery, VFX, native 3D filmmaking, the emotional thrust of Battle Angel is focused on a Cyborg life form looking to fulfill her human potential.
The use of real-time digital capture of the human face, allowed for an actor’s natural expressions to be fully mapped and translated, in this case actress Rosa Salazar into the Alita character we seen on screen.
Other VFX and CGI effects can be seen as usual in other characters and other parts of the movie as well.
It is always have been difficult in maintaining to what extent the CGI should be used in these kinds of movies. Movies like the Star Wars Special Editions and Green Lantern have been heavily criticized for overusing computer graphics. In the case of Alita, finding the balance wasn’t easy.