What is CGI? How CGI Works in Movies and Animation

CGI Meaning

CGI definition and characteristics

What is CGI? What does CGI stand for? Any CGI definition is bound to be very broad because it does not narrow itself to just one type of visual effect. In fact, the definition of CGI includes everything from background set extensions to fully animated characters and environments. So, before reviewing the most notable examples, let’s define “What does CGI mean?” and clarify the broader CGI meaning in a way that covers most of its uses. 

Whether through live-action footage enhanced with CGI effects or fully animated films, it continues to shape how we experience stories on screen. What does CGI stand for? CGI stands for computer-generated imagery, a technology that enables filmmakers to create everything from small visual effects to entire animated worlds. 

VFX vs. CGI vs. SFX

What’s the Difference?

Before we compare VFX  to CGI, let’s briefly restate the CGI meaning. First, though, it’s worth understanding the vfx meaning, which includes both digital and practical enhancements applied to live-action footage. VFX (Visual Effects) refers to all digital and practical techniques used to enhance live-action footage, often blending real and artificial elements.

CGI (Computer-Generated Imagery) is a type of VFX that specifically involves creating digital images, from 3D characters to entire environments. It’s commonly used in animation, sci-fi, and fantasy films.

SFX (Special Effects) are practical, in-camera effects like explosions, prosthetics, animatronics, and weather effects, achieved before digital post-production.

Think of it this way: VFX is the magician, CGI is the illusion, and SFX is the hands-on trickery. Together, they shape the cinematic worlds we love—whether it’s a roaring dragon, a collapsing city, or an actor aging decades in seconds.

History of CGI

When was CGI invented?

When was CGI invented? The origins of computer-generated imagery (CGI) date back to the 1960s, initially developed for scientific applications. Understanding the historical meaning of CGI. helps us appreciate how far visual storytelling has evolved. Hollywood adopted CGI in the 1970s, using it in movies like Star Wars (1977) and Alien (1979). At the time, the definition of CGI was still evolving, limited to wire-frame models and simple digital renderings. In the beginning, directors like Alfred Hitchcock and George Lucas played a role in advancing how computer-generated imagery was used in filmmaking.

Be sure to watch the video below—it’s a landmark moment in the history of CGI and worth highlighting here.

Most of this was two-dimensional in scope, but all of it was being used in disciplines ranging from science to engineering and later medicine.

As CGI technology evolved, so did the ways filmmakers sought to use it in their films, which are among the first CGI movies in cinema. They could create digital viewpoints in Westworld (1973) and wire-frame models in Star Wars and Alien, though their usage and scope were still limited at the time. 

The role of CGI would evolve even further in the 1980s, with films like Tron (1982), The Last Starfighter (1984), and Young Sherlock Holmes (1985) making use of the technology to create full models of real-life objects and life-like characters.

So when people in the movies and movie fandom refer to CGI technology today, they are nearly always talking about VFX work. This can include 3D models of people, monsters, buildings, cars, explosions, and many other things. These 3D models are then put into a live-action scenario, such as a monster attacking a city or a car being blown up by an explosion. These types of CGI effects are commonplace and are often seen in high-profile productions.

CGI can be seen in many genres across film. In a period drama, for example, it can be used to fill out locations with period-specific details, as well as maintain consistent scenery, e.g., background environments full of buildings, people, and vehicles. In a science-fiction blockbuster, CGI can be almost 90% of everything you see, from the characters, vehicles, environments, and actions. CGI is proliferating today as innovations like motion capture and 3D models are now common tools for filmmakers, who combine green screen technology with advanced-generated imagery to create hyper-realistic sequences.

CGI Examples

CGI examples past and present

When was CGI invented? The origins of CGI date back to the 1960s, long before it became a staple of modern filmmaking. The history of cinema is full of various CGI examples from all types of film genres. Some of those examples are small but notable moments in a regular movie, while other examples are the entire film itself (like in animated films, which we will cover in detail later). 

Creating a storyboard is the first step to visualizing CGI. Using storyboarding software is the first step in pre-visualizing CGI sequences, helping filmmakers shape their vision. In the below example, using StudioBinder’s storyboard application, we can explore key CGI milestones—from Westworld’s early digital effects to Toy Story's groundbreaking animation and modern spectacles like Spider-Man: Into the Spider-Verse and Avengers: Infinity War.

How CGI Works

How CGI works in filmmaking

Computer generated imagery is created through a multi-step process involving advanced software and technology. Here’s a brief rundown of how it works: 

1. Concept & Previsualization – The process begins with concept art, storyboarding, and previsualization (previs).
   • Concept artists create initial sketches and paintings to define the look of characters, environments, or effects.
   • Storyboarding lays out the sequence of shots, ensuring continuity.
   • Previsualization (using 3D animatics or rough models) helps filmmakers plan camera angles, movement, and visual effects integration.
2. 3D Modeling – Artists create digital 3D models of characters, environments, vehicles, and objects using software like Maya, Blender, 3ds Max, or ZBrush.
3. Texturing & Shading – Once the model is created, textures and materials are applied to give it a realistic or stylized appearance. 
   • Texturing involves mapping 2D images (textures) onto the 3D surface to add details like wood grain, skin pores, rust, or fabric patterns.
   • Shading determines how the model reacts to light, reflection, and transparency. Different shaders (like metal, plastic, or glass) define how surfaces interact with the environment.
4. Animation & Motion Capture – Movement is added to the CGI models using various techniques: 
   • Keyframe Animation: Animators manually create poses at key points, with software interpolating movement between them.
   • Motion Capture (Mo-Cap): Real actors wear special suits with tracking markers, and their movements are captured by cameras to apply to digital characters (commonly used for lifelike performances, e.g., Gollum in The Lord of the Rings).
   • Rigging: A process where a digital skeleton (rig) is created inside the model, allowing it to move realistically.
5. Rendering & Compositing – The final stages involve generating the complete CGI images and integrating them into live-action footage. 
   • Rendering: The software calculates lighting, reflections, and shadows to generate photorealistic frames. This can take hours or even days per frame, depending on complexity.
   • Compositing: The CGI is layered into live-action footage using programs like Nuke or After Effects. This step ensures CGI elements blend naturally with real-world elements through color grading, depth of field, and additional VFX enhancements.
     
     

CGI creation is a complex but highly refined process that blends artistry with advanced technology. From initial concept art to final compositing, each step plays a crucial role in ensuring realistic and seamless visual effects. When executed well, CGI enhances storytelling without drawing attention to itself—making the impossible look effortless on screen.

CGI vs. Practical Effects

Striking the perfect balance in film

Many filmmakers debate when to use CGI versus practical effects. Both techniques have their strengths and weaknesses, and a well-balanced approach often leads to the best results.

Over the years, audiences have grown increasingly critical of CGI, especially when it is poorly executed. A deeper understanding of the CGI meaning helps viewers distinguish between subtle enhancements and overused visual trickery.

This has led to an ongoing discussion about why filmmakers opt for CGI over practical effects in certain situations. While bad CGI can pull viewers out of the experience, seamlessly integrated CGI can be virtually invisible, enhancing scenes without drawing attention to itself. This balance is key to the true meaning of CGI in modern cinema.

As the video below illustrates, the most effective CGI is the kind you don’t even notice, working behind the scenes to bring a director’s vision to life.

Most movies that use special effects and CGI will often balance it out with other VFX work. The VFX meaning encompasses various visual techniques, from subtle digital compositing to large-scale set extensions.

Jurassic Park (1993) might be the gold standard of this, as it used CGI along with practical effects to create realistic-looking dinosaurs. This approach remains influential, even as CGI software and animation software continue to evolve, allowing 3D animators to create increasingly lifelike imagery.

CGI Animation

What is CGI Animation?

What is CGI animation? No area of cinema has embraced this tech more than fully animated CGI movies. Stop motion animation was a fairly popular style for a while, even while many animated movies were still hand-drawn. It was the closest filmmaking got to three-dimensional animation, but it took time and a lot of effort to get done. It also took a long time, since stop-motion requires you to map out each bit of movement that will be shown on-screen.

Soon computers began dominating the arena of hand-drawn and stop-motion animation with CGI. This technology made it possible to create three-dimensional worlds that were not constrained to actual live-action filmmaking. Not only that, but computer animation allowed filmmakers to be as realistic or as fantastical as they wanted.

Pixar was among the very first to experiment with fully computer generated animation, as seen in early Pixar short films. These early projects redefined the meaning of CGI as a storytelling medium capable of emotional and visual depth.

Toy Story (1995) became known as the first CGI movie done completely with computer animation, which alone could make it notable. However, the movie was also critically acclaimed and a financial hit; it’s known as one of the best animated movies of all time and inspired beloved sequels.

Other studios decided to try their hand at CGI animation, like Dreamworks, who first put out Antz (1998) with positive results. However, if any movie put them on the map for good, it was Shrek (2001), which was a massive success and had a major influence on children’s animation.

Since the beginning of the century, there have been almost too many CGI animated films to keep track of. Disney themselves committed to this style over ten years ago when they started putting out their 3D animated work outside of Pixar. These days, 2D animation seems relegated to television, where even then shows using 3D models can still compete.

While Pixar, Disney, and Dreamworks dominate family-friendly animation, studios like Illumination have broken through to create their brand of 3D-rendered films. Even though they’re relatively new to the scene, hits like Despicable Me (2010) and The Secret Life of Pets (2016) have proven that the space of CGI animation is still very much evolving.

The Power of CGI

How the technology is evolving

CGI is often associated with blockbuster budgets, but independent filmmakers can use it effectively with careful planning. Including cost-saving tips and cost breakdown. Maybe you want to replicate something you’ve seen but think you don’t have the resources when actually, you do. Our article on Inception’s Paris cafe scene not only breaks that scene down but shows you how you can pull it off using our software.

Many CGI movies utilize the technology to do things they could never do otherwise. The CGI meaning extends far beyond spectacle—it’s about enabling directors to realize scenes that would be impossible through traditional means.

James Cameron movies are known for their CGI since that same tech was what made the T-1000 in Terminator 2 (1991) possible. It also made Titanic (1997) that much more effective, with its use of CGI models along with actual sets. More recently, Avatar (2009) demonstrated Cameron at the top of his visual game, using various VFX in combination with CGI to create a unique experience.

Other movies that use CGI utilize it in ways we won’t even notice, such as adding more textures, characters, or objects in an environment. For example, a shot of a real city can be manipulated to include additional buildings, people, and cars on the street, lights, or shadows. Zodiac (2007) used extensive CGI for creating environments, and other features of those environments.

CGI effects may have been mainly used for fantastical movies at first, but plenty of filmmakers in different genres have taken advantage of it. It’s also no longer as expensive or limited as it once was, allowing more movies to take advantage of the tech. In some genres, such as children’s films, it has become the dominant form for making these types of movies.

CGI Future

The Future of CGI

Emerging technologies like AI-driven animation and real-time rendering are pushing CGI boundaries. Virtual Production, allows filmmakers to shoot in dynamic digital environments without post-production CGI additions. This technique expands the VFX meaning to include real-time, in-camera effects as part of the modern visual pipeline.

It might then be expected that those at Lucasfilm and Industrial Light & Magic (ILM) are the ones at the head of this innovation with something they call StageCraft, aka “the Volume,” which is used on the hit Disney+ show The Mandalorian.

As they did back in the day, Lucasfilm and ILM have created a new groundbreaking way to shoot VFX in-camera (as opposed to in post-production) that unites practical staging with computer-generated imagery.

StageCraft combines the powers of several different companies, including Epic Games, whose Unreal Engine has been behind the VFX for other productions over the last few years (and video games, of course). The Unreal Engine and its use of computer technology are key parts of what makes StageCraft as effective and ingenious as it is. 

Watch our video to see how virtual production blends real and digital elements seamlessly, solving issues that traditional green screens couldn’t. Pay close attention to the advantages it offers—like immersive lighting and real-time environments—while also considering its current limitations.

StageCraft is the ultimate response to green and blue screen technology. Instead of having a colored sheet to make your imaginary backgrounds (which are placed in post), why not project those backgrounds while the actors are performing on the set? So instead of having actors act in front of green or blue screens, they can act in the (projected) environment they are meant to be in. Take a look at how it was used in the video below.

Aside from being a great thing for the actors, StageCraft, above all, makes everyone’s job easier. Using a 270-degree area made of LED screens, the environment for the shot (CGI or real) is displayed on the screen as the cameras are rolling. Combined with lighting and props on the set itself to create the scene as if the actors were there, be it a desert landscape or icy tundra. The result is a realistic-looking scene that is all done in camera, on set, and in real time.

It’s still a bit early, but StageCraft is already making waves and wowing everyone, including those using it. Not everyone has access to StageCraft, of course, but it is a safe bet that this technology will find its way into more projects soon, at least within Lucasfilm.

UP NEXT

What is VFX?

We have gone over the basics of computer-generated imagery, but now it’s time to dig into more general visual effects. Here you’ll get an overview of VFX featuring specific examples, terms, and types that can be found in familiar television programs and movies.

Up Next: Explore more about VFX →