What is CGI, Anyway?

Surely you’ve heard the acronym CGI before. We’re guessing that’s why you’re here. Maybe you just got out of a movie, and one of your friends made a comment on how poor the CGI was. This may have left you wondering, what is CGI, anyway? And, what does CGI stand for?

Well, simply put, CGI stands for computer-generated imagery. So CGI is actually a really broad term and can apply to a lot of different types of computer-generated media. Here at Daz 3D, we’re experts at 3D rendering and character creation, and if that excites you, stick around to learn all about CGI.

Types of CGI

CGI is a broad term that covers lots of different types of images. CGI is all around us, and sometimes it comes in forms you may not have ever considered to be CGI. Nowadays, when you watch a movie you are sure to see VFX, or virtual effects. Movies save money and expendable resources by hiring talented digital artists to create virtual effects in their movies. This could be as easy as creating a virtual explosion, or as complicated as rendering skyscraper-sized monsters that completely obliterate Los Angeles while fighting.

2D

This can be a bit of a misnomer and gets a little complicated. Obviously, screens are flat, so even images we call 3D are technically 2D.

So what does it mean to work in 2D? Well, in CGI, something created in 2D only uses 2 axes in its development, X and Y. In terms of shapes, this means you are working with circles, squares, triangles, and so on. The key distinction is you are not relying on computer programs to simulate the third axis like you would in 3D CGI.

Many cartoons, like Disney motion pictures and anime, are 2D CGI. The same is true for most graphic design and other forms of computer-generated traditional art. For example, an image manipulated in Adobe Photoshop would be considered 2D CGI.

3D

This is what everyone most commonly thinks of when it comes to CGI. 3D can get a little more complex since creators have quite a few more variables to worry about. 3D programs try to simulate the real world. To do this, the computer stores a large amount of information about the “3D” object, including how it looks from every possible angle. That way when the view is changed or the object is turned or rotated, the computer continues to display the object as it would look if it were rotated in real-life.

Another important aspect of 3D CGI is lighting and how an object appears when lit. If you’ve ever taken an art class and had to sketch an object, you’ve probably been exposed to these basic principles. When light is directed at an object, it creates shadows and highlights and a single light source can’t cover the entire surface of the object perfectly and evenly.

This is where 3D software comes in. The software does the math and determines how the light should behave with the object in question. While this may seem like an oversimplification, it does well to explain the very basic foundation of 3D. To get a better idea about how lighting works as a tool in 3D CGI, check out our blog post all about lighting.

Another crucial aspect is material and texture creation. On its own, a 3D model only displays the shape and form of an object. 3D artists use textures, materials, and things called maps, to dictate how the surface of a 3D object appears. When HD source materials are used, the results can be surprisingly lifelike or edgy and stylized.

Finally, 3D software performs an important task called rendering. This is where all the information is officially computed, thus generating a static image known as a render.

CGI Animation

So, what good is a single render? How do CGI artists create entire TV shows, movies, and commercials? Well, believe it or not, a “motion picture” is nothing more than thousands of images played in sequence — usually 30 images per second. The same is true of video games, which we typically prefer to consume at 60 frames per second.

So if an animated movie is 2 hours long — a total of 7,200 seconds — and the movie is set at 30 frames per second, that means the movie is made up of 216,000 individual images or frames. That’s a lot of images!

Now consider how much time and effort goes into creating each one of those frames. There’s modeling, animation, lighting, and synchronization. Sound effects, dialogue, background music, and so on. All of this adds up to a lot of time. Take Pixar for example — each frame of their movies can take anywhere from 45 minutes to 30 hours to render, depending on how complex the frame is. So how on earth do they manage to produce so many movies? The answer is lots and lots of powerful hardware! At any given time, they probably have dozens of machines working around the clock rendering their images.

AI

With the rise in machine learning, you may be interested in AI-based CGI. There are several new programs released into the wild you can try these days. They all specialize in different things or achieve very different results. The cool thing about many of these AIs is their flexibility in the kind of media they create.

For example, Midjourney is an AI that has been taking Discord users by storm. Depending on the type of image you want, it can render 2D drawn styles, or even highly-detailed renders that look like they were done in the best 3D software available.

Working with AI is exciting, fun, and unpredictable, and you don’t have to be a pro or have any digital art skills prior to getting started with it.

Learn CGI for Free

Learning CGI is a great hobby, and can even lead to a solid career path as well. With the rise of CGI and VFX in so many industries, there is high demand for skilled digital artists. There are many ways to learn, though we believe Daz Studio is an excellent place to start. Our software is totally free to use, and we have several useful tutorial videos. These videos walk you through everything from designing your character from our immense library, to setting up lighting and creating your final render or animation.

To learn more and get started, download your free copy of Daz Studio today!