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  • Manya Kumar

CGI: The Complete Guide

CGI has been constantly evolving; today it is at a point where we can’t distinguish between CGI effects or real shots in a film. So, let’s understand CGI in depth- its history, how it changed the cinema industry, and much more.

“The nature of the movies is different than it was five years ago, and they're all driven by the possibilities of CGI, which means you can make anything happen on screen that you can possibly desire.”- Tom Hanks

Did you know that Timothee is wearing an earpiece in this scene, but it was CGIed out later?

What is CGI?

CGI stands for Computer Generated Imagery. CGI is a broad category of media classification, covering rendered images and many other types of digital imaging. It is a common misconception that CGI only covers objects rendered in 3D, but that is incorrect. CGI can be both 2D or 3D animations, objects and renderings. Industries like television, films, video games, simulations, and multiple other fields use CGI. Today CGI is not limited to sci-fi movies- it can be used in films of any genre. CGI is created using different methods:

  • Using algorithms can create complex fractal patterns.

  • 2D pixel-based image editors can produce vector shapes.

  • 3D graphics software can generate everything from simple primitive shapes to complex forms created from flat triangles.

  • 3D software can simulate the way light reacts to a surface and creates particle effects.

CGI has become the bridge between directors and the director’s vision for the movie; CGI has made it possible for directors to meet with their ideas for the movie that wouldn’t be realistically possible to achieve.

A CGI model

History of CGI

With the basic idea of CGI out of the way, let us trace CGI back to its roots and understand it in depth. I have mentioned some notable milestones in the history of CGI if you want to read more in-depth you can read the Timeline of CGI in Film and Television or watch the video below.

First computer animation- Alfred Hitchcock- Vertigo- 1958

Alfred Hitchcock’s ‘Vertigo’ marked the beginning of CGI incorporated in feature films. At that time, mechanical computers had just been repurposed to create patterns on animation cels.

First computer-animated short film- Edwin Catmull and Fred Parke- A computer-animated hand-1972

Though Hitchcock was the first to introduce CGI to the cinema, CGI didn’t get attention until 1972. Edwin Catmull and Fred Parke had made an animated short film called ‘A Computer Animated Hand’. The short film was the starting point of 3D computer graphics. This feat was achieved by drawing 350 triangles and polygons in ink on Edwin’s hand and finally digitizing and animating it in a 3D animation program made by Edwin himself.

First digital animation in a feature film- Westworld- 1973 Westworld took it a step further by adding the first 2D CGI scene. The scene was intelligently shown as the Gunslinger’s vision- it was a creative interpretation of a robot’s vision.

First 3D animation in a movie- Futureworld- 1976

Futureworld became the first movie to include a 3D rendered head- it was created by the same principles as Edwin’s animated hand. Not only that, but the movie also incorporated the hand Edwin created.

It took years for computers to fully harness the power of CGI and to allow directors to bring their visions to life. By the end of the ‘70s, computer-generated imagery started popping up in a few science fiction movies such as The Black Hole and Alien.

In 1982 ‘Tron’ was released, the movie didn't break records at the box office, but it did go on to eventually win an Academy Award fourteen years later. Other movies like ‘The Last Starfighter’ (1984) and ‘The Abyss’ (1989) also made their contribution to the progression of CGI.


The Abyss

By the time the 90s came around, CGI was all the rage, and many companies wanted to try their hand at it. The 90s gave us some of the most iconic movies till date- Terminator II: The Judgement Day (1991), The Lawnmower Man (1992), Toy Story (1995), Star Wars Special Editions (1997), The Matrix (1999).

Toy Story

The Matrix

Leading the charge with many of these movies were ILM, Stan Winston Studios and Phil Tippett, who dropped arguably the best CGI of all time - Jurassic Park (1993). The bar was set so high with this; many CGI artists strongly believe Jurassic Park has the best visual effects to date. What really changed at this point was how they used a mix of real actors, animatronics and CGI to bring dinosaurs to life alongside the actors which has never been successfully done before.

CGI only kept evolving- by the time 2000s and 2010s came around we had legendary movies like Kung Fu Panda (20018), Avatar (2009), Inception(2010), Captain America: The First Avenger (2011), Interstellar (2014) etc.


Types of CGI

The period before the advent of CGI wasn’t all fun and games- the efforts put in were much higher, which didn’t necessarily promise the expected output. As CGI emerged and became more appealing and exciting to watch, filmmakers immediately got on board. With the advancement of technology, CGI has branched into different types, they are as follows:

1. CGI Animation: These are short or feature films that are animated entirely. There are no real-world elements involved- they are purely fantasy and imagination.

The Incredibles

2. Composite CGI: Composite CGI involves combining two or more images to make a single picture. Greenscreens are used to achieve this; you can easily change backgrounds or any element of the scene to your liking using a green screen.

The Great Gatsby

3. Mo-cap CGI: Motion capture CGI essentially records the movement of objects or people and use that information to animate digital character models in 2D or 3D computer animation.

Key Roles and Departments

The process of creating CGI is long, challenging and very technical. The teams are diverse, which means there are opportunities for everyone- from hardcore coders to illustrators to even non-artistic opportunities like team managers. Let’s walk through some of the important roles that one can pursue according to their interests.

1. Art department The art department translates the director’s vision and helps all the teams to visualise the script and understand the road map ahead to create the final project. The art department consists of concept artists, illustrators etc, and they make everything from storyboards to photorealistic artworks.

Art Department: Then

Art Department: Now

Art Department: Now

2. Pre-viz

The pre-viz team (pre-visualisation) are responsible for producing the first 3D model of the final visual effects shot. They do so by using artwork and basic 3D models to create a usually low-quality version. This model allows the director to plan the camera placements, creative/technical requirements well in advance of the shoot.

3. Asset department

The job of this team is to create visual effects that match real-world objects or create new objects that are too expensive to build in real life. The asset department comprises modelling artists, texture painters, shaders, developers and riggers.

3D Rendered Car

Before: 3D model

After: Rendering of the model with shader, lighting, compositing effects applied

4. Research and Development

The RnD department is responsible for building new software and tools to ease the process of accomplishing tasks. This job profile requires a very strong background in computer science and a knack for problem-solving. You can read how Disney and Pixar’s RnD team operate.

5. Animation

As the name suggests, this team animates any stationary object/ character.

6. Matchmove

It would be impossible to incorporate 3D data into live-action footage without motion tracking. The matchmoving team makes the digital assets appear real. Matchmove artists have to use the live-action footage and create a virtual camera (digital assets that mimic the live-action footage) for all departments to work with.

7. FX simulation

A highly technical, yet creative role. FX artists are responsible for recreating the behaviour of real-world elements such as hair, cloth, fire, water and so many more!

8. Lighting

All lighting effects that are applied to a digitally created scene are taken care of by the lighting department.

9. Matte paint

A matte painting is created using digital and traditional painting methods to create a representation of a scene/location that is not possible to travel to or doesn’t exist, or just to make the set look more in accordance with what the shot needs.

Matte Painting: Before & After

10. Rotoscoping

Rotoscoping artists create animated sequences- the process is carried out by tracing live-action footage frame by frame. It is a time-consuming job, but a crucial role.

11. Compositing

It is layering of various elements like live-action, animation, lighting etc. to produce a final shot. Everything needs to be blended together in order to make a seamless and photo-realistic final shot.

12. Production

For the people who prefer managerial roles, the production team is the ideal job. The top production role at a studio is VFX producer; VFX producers and VFX supervisors together manage the entire process, planning and defining the resources required, hiring artists and crew, managing budgets, managing time to make sure all the deliverables are delivered in time etc. All production managers and production coordinators have a lot to manage and deliver.

Advantages and Disadvantages of CGI

Everything comes with its pros and cons, so does CGI- here are a few plus and minus points to keep in mind before you use CGI in your next projects.


1. Freedom for the director

Filmmakers can easily resort to using CGI whenever reality is not meeting their standards- with CGI filmmakers have a lot more room for creativity. CGI can be used to stimulate weather effects, add or remove crowds from streets or sidewalks and many more according to the filmmaker’s vision.

2. Optimizes time

CGI not only unlocks new bounds of creativity but also saves the team a lot of time. CGI eliminates the need for setting up and using green screens to create unrealistic imagery. It cuts down on the time spent on retakes or any other processes. Creators can directly go into the process of making backgrounds and putting the characters in to make a movement, audio and scenery.

3. Ability to tweak character’s looks

It is possible for the director to be dissatisfied with the final output of the shot/ scene. It is not feasible to reshoot because it would cost money and time. This is where CGI can come in handy- it allows things to be changed no matter how minor, even if it’s a hairstyle or colour of clothing. It can be changed.

4. Saves Money

We are well aware of all that can be done from the simplicity of a computer. CGI takes away the need to have to pay for set, set spaces, a large crew, costumes, makeup etc. CGI has made it possible to create what would be physically impossible to create or would cost vast sums of money.


1. Highly skilled technicians needed A good CGI created shot/ scene/ film means, one needs to be highly well-versed with the appropriate software. Not only that, but it takes up a lot of time of the technician’s life, and they are on a strict deadline to produce the film. The technicians have to constantly keep up with the updates of the software to produce the best quality work.

2. The difficulty of animation When a designer is creating a full-on animated scene, they strive to make it as realistic as possible. Regardless of all the efforts, it is difficult to achieve movement in correlation to the laws of physics. From the audience point of view, it may not appear that anything is wrong with the animation, but on looking closely, things won’t look as realistic. When an animation fails to deliver realism, it takes away the effects CGI can have, and it loses its power.

3. The price of CGI Even though CGI does save time and money, the hardware and programming can cost a lot of money. Special programmes are needed to ensure no data is lost and all is edited perfectly. For example- the popular show “Game of Thrones” had a combination of CGI and real-life elements. It was found out that if a Game of Thrones episode has 10 minutes of CGI, it would cost $800,000. It would be even more expensive for a movie that is completely made from CGI.

4 CGI wizards

Now that we have understood all the details, from what is CGI to key departments and roles one can pursue. Let’s take a look at some of the greatest VFX experts in Hollywood and gain some inspiration.

1. John Dykstra

“Digital imaging has untied our hands with regards to technical limitations. We no longer have to be arbiters of technology; we get to participate in the interpretation of technology into creative content.”

John Dykstra is one of the most talented VFX artists. His admirable work in Star Wars isn’t iconic just for the effects, but also because he invented motion-control photography while working on the movie.

Awards: Dykstra has won two Oscars for Star wars (1978) and Spider Man-2 (2005).

Notable movies: Stuart Little (1999), Inglorious Basterds (2009), X-Men: First Class (2011), Django Unchained (2012), Godzilla (2014), X- Men: Apocalypse (2016), Once Upon A Time In Hollywood (2019)

2. Ken Ralston

“You have to keep growing quickly and in big ways to accomplish the work. The only way to grow is by being challenged in terrifying ways. If you get there, you learn so much.”- an interview with AWN

Ken Ralston is currently the Visual Effects Supervisor and Creative Head at Sony Pictures Imageworks. He is a risk-taker and believes in experimenting.

Awards: Five Oscars, for Star Wars: Return of the Jedi (1984), Cocoon (1986), Who Framed Roger Rabbit (1989), Death Becomes Her (1993), Forrest Gump (1995). Ralston also bagged five BAFTA Awards.

Notable movies: Dragonslayer (1981), The Mask (1994), The American President (1995), Men in Black 2 & 3 (2002, 2012), The Polar Express (2004), Alice in Wonderland (2010), Alice Through the Looking Glass (2016)

3. Erik Nash

“Visual effects are playing a bigger role in movies that, on the surface, do not look like big visual effects movies.”- an interview with Studio Daily

Nash is an expert in motion control photography. His way of manipulating the camera to produce life-like shots is unmatched. He spent seven years on TV’s Star Trek: The Next Generation doing motion-control photography. While Nash was working on Titanic, he devised an algorithm to produce the elaborate sweeping camera effect.

Awards: Nash is a two time Emmy winner for Star Trek: The Next Generation in 1992 and 1994.

Notable movies: Apollo 13 (1995), Titanic (1997), Armageddon (1998), Pirates of the Caribbean: At World’s End (2007), Real Steel (2011), Avenger Assemble (2012), Iron Man 3 (2013)

4. Dennis Muren

“Everyone is trying to do something that hasn't been done and that's a really good thing. You can only do so much with a story and some scripts don't give you the opportunities and other scripts do give you the opportunities to do things that haven't been done before.”

Dennis Muren is the Senior Visual Effects Supervisor and Creative Director of Industrial Light & Magic. Muren has actively been a part of designing and developing new techniques and equipment. He is also the first visual effects artist to be honoured with a star on the Hollywood Walk of Fame.

Awards: Muren has won six Oscars for E.T. the Extra Terrestrial (1983), Indiana Jones and the Temple of Doom (1985), Innerspace (1988), The Abyss (1990), Terminator 2: Judgment Day (1992), Jurassic Park (1994). He also won four BAFTA Awards.

Notable movies: Young Sherlock Holmes (1985), Ghostbusters II (1989), Twister (1996), A.I. Artificial Intelligence (2001), Hulk (2003), War of the Worlds (2005), Paranormal Activity 4 (2012)


CGI has been a topic of debate for some time now- while many are in favour, many believe it is a shortcut for lousy filmmakers. Regardless of what the world thinks, there is no denying that computer-generated imagery has changed the face of cinema; it has allowed filmmakers to set new standards of reality in films. While I am praising CGI, it’s necessary to keep in mind that- it can easily go wrong if you are not skilled enough. The art of computer graphics, though creative, it is extremely technical. Hundreds if not thousands of artists work to create good CGI in movies. Viewers are critical towards CGI, but that doesn’t mean it holds the upper hand and is the reason for a movie to be good- the story is king. Computer imagery exists to complement the story; here are some bad exampled of CGI:

CGI can be used subtly or not-so-subtly, it is how seamless you make them look in the film is what good CGI is all about. Remember, with the power to edit every single pixel comes the great responsibility of knowing how much you need to change to not go from great to tacky.


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