What is CGI (Computer-Generated Imagery)?

Blog header

What is CGI header

CGI has had an incredible impact in movies. Cinema has greatly evolved and incorporating computer generated imagery has been one of the most important advances that the industry has made. it is vastly used in movie genres and it’s a great tool for visual effects. Some important questions relating to the CGI world are “Will CGI replace actors?” “When did CGI become popular?’, “Who invented CGI?”and “how does CGI work?”. If you don’t know what CGI is, you are in the right place. In this article, we will cover everything there is to know about CGI. 

What Is CGI?

You might be wondering, what does CGI stand for? Well, it stands for Computer-Generated Imagery which, basically, is the creation of animated visual content using computer software. In some cases it may be referred to as 3D imaging. CGI is usually used to create 2D or 3D characters, and all sorts of special effects in films, television and video games. You can also find CGI in visual arts, advertising, architecture, engineering and so many other fields. CGI can be in your favorite science fiction movie as well as a dramatic movie making it a widely used visual medium around the world.

CGI comes in handy when you need to create visuals that are not humanly possible and it is more accessible than you think. It can save you the cost of hiring extras or creating sequences using miniature figures. And believe it or not, CGI has been around about 70 years. 

When Was CGI Invented?

This technique was invented around the 1950s. At that time, analog computers were used to create patterns onto animations which were then included in featured films. And you might be wondering, which was the first film that used CGI? Well, we have an answer for that! The first film to ever used it was Alfred Hitchcock’s classic Vertigo made in 1958. This was the first computer animation used in film. Most animations during that era were very basic 2D compositions.

What is CGI vertigo
Vertigo (1958) by Alfred Hitchcock.

3D computer graphics were introduced in 1972 when Edwin Catmull and Fred Parke made a short film titled A Computer Animated Hand. The film was fully computer-animated, a feat made possible by Edwin drawing 350 triangles and polygons in ink on his hand and then digitizing and animating that data on a 3D program that he wrote. 

What is CGI animated handA Computer Animated Hand (1972) by Edwin Catmull and Fred Parke.


When Hollywood came into the picture, CGI took a leap forward and in 1973, Westworld by Michael Crichton, featured the first 2D CGI scene depicting a robot’s ability to perceive vision. After this successful implementation CGI started appearing more and more. Some movies from that era that featured Computer Generated Imagery are Alien (1979), Star Wars (1977), and Tron (1982). 

What is CGI Westworld
Robot’s ability to perceive vision. Westworld (1973) by Michael Crichton.

By 1990, new techniques emerged and great ideas were able to be produced using CGI. Some amazing movies in the 90s that adopted computer aided imagery include Terminator 2 (1991), Titanic (1997), The Matrix (1999). However, the movie with the best CGI of that period is unquestionably Jurassic Park (1993), which achieved amazing visual effects thanks to a mix of real characters, animatronics and CGI bringing dinosaurs back to life in a spectacular manner. 

What is CGI JP
Jurassic Park (1993) by Steven Spielberg.

Another movie that was a real success, was Toy Story (1995) which was entirely directed with CGI which had never been done before. Later, Pixar produced more CGI movies like Monsters, Inc. (2001) and Finding Nemo (2003). 

Toy Story (1995) by John Lasseter.

From 2000 and onwards, CGI was taken to a whole new level. With new technologies emerging in the film industry, CGI was able to grow and improve. Nowadays, it is a fundamental part of films. The movie Guardians of the Galaxy (2014) heavily relied on this technique since 90 percent of the movie features it in some capacity. Filmmakers in various genres now continue applying computer generated effects even though it was initially used in fantasy movies. 

How does it Work?

CGI is created by algorithms that make complex fractal patterns mixed with 2D pixel-based image editors creating vector shapes and animation softwares. 

The process consists of 8 parts:

  • Modelling: This is defined as the process of building 3D objects that feature in animations. This process can be carried out in different ways, for instance, 3D digital sculpting or laser scanning.
  • Texturing: The next step of the process is texturing. Here materials are added to the 3D objects to make them look real. Often, the 3D objects have a default gray color and sometimes you need to put 2D images with the desired texture.
  • Lighting: This part of the process is fundamental for great results. To achieve the perception of reality, just like in a real film set, you’ll need to adjust the size, number and direction of cinematic lights you use. This step is super important, so don’t forget about it!
  • Camera: You’ll definitely need a camera in your 3D scene, You can choose a regular camera which moves freely or a target camera that is locked and aimed at a particular point.
  • Animation: So now let’s get some movement! This is where all the fun is. You can make your 3D objects move, usually with a timeline that will allow you to adjust some settings. Take note that animating the camera is very important.
  • Simulations: This is not an essential step, but keep in mind that simulations are crucial when you want to create realistic images of liquids, fire, smoke and other effects.
  • Rendering: This is the process where everything is put into files that you can later be seen in a visual format. Rendering requires a lot of knowledge and even though most CGI animation softwares include their own rendering applications, most animators decide to use external rendering platforms for their final product.
  • Composting: Okay, so this is the final step of the process. It involves refining the look of the rendered content, for example, shadows, lighting, reflections, colors, etc. 

This is basically the process of CGI and most animations follow all (or most) of these steps in a similar order. When it comes to movies, various units like the Art Department, the Asset Department, the Research and Development Department, the Animation Team and many others are involved in the creation of computer generated visuals.  

Groundbreaking Movies

CGI can make impressive visual effects that leave an audience amazed. Here are some movies that have made spectacular breakthroughs thanks to computer generated imagery.

The Irishman (2019) by Martin Scorsese is a movie that made a very good use of CGI. They managed to make Robert De Niro, Joe Pesci and Al Pacino look way younger on screen. We see the transition of these characters from their 20s to their 60s and in order to do this, they used de-aging technology. Most of Robert De Niro’s on-screen time in this movie is computer-generated. They needed at least 3 different cameras on the actor’s face and a software which detects the differences between light and shadow. This software, then, uses each pixel as a marker to render a computer-generated version of De Niro’s face. Incredible, right?

What is CGI DeNiro
The Irishman (2019) by Martin Scorsese.

Avatar (2009) from director James Cameron, is another movie that used CGI in a way that has never been seen before. It was not only filmed in 3D, but also 70 percent of the film content is computer generated. It is one of the most expensive movies ever made and arguably the best use of CGI in history. 

What is CGI avatar
Avatar (2009) by James Cameron. 

The movie Matrix (1999) enters this list as an honorable mention based on the brilliant execution of a visual effect known as “bullet time”. The scene where Keanu Reeves dodges a hail of bullets in slow motion as the camera runs at normal speed is the highlight of the blockbuster and the visual technique was pioneered in that sequence.

What is CGI matrix
Matrix (1999) by Lana Wachowski & Lilly Wachowski.

There are tons of movies worth mentioning but we could only highlight a few memorable ones. We hope you have gained some insight on the importance of this groundbreaking industry technique and how it has taken its effect on today’s movies.