What is computer animation?

3D computer animation is a mix of 3D models and traditional frame-by-frame animation. Much like historic stop motion techniques, digital animation creates the illusion of movement by repeatedly replacing the 3D model with a new and similar image, but advancing the frames per second for each new image (keyframing). This can be used to create animated films, or simulations that require complex motions, like those in the medical field.

These 3D images are modeled on a computer and rigged with a digital skeleton. This enables 3D computer animators to move individual elements, like eyes or lips, by using keyframe systems to ensure a smooth transition between the start and end of a movement, such as blinking. The computer automatically calculates the difference in appearance between keyframes, and when all keyframes are complete, the animation can be rendered.

Animators can also use motion capture (mocap) devices to track a real-life actor or object, and then digitally animate on top of them. Much of 3D computer animation is a mix of keyframing and mocap techniques.

Computer-generated animation is a digital form of traditional stop motion animation techniques that would use drawings or scale model puppets. This form of animation dates back to the magic lanterns of the 17th century, where a mirror would direct candlelight through glass slides to project the illustration. Placing slides together created a sense of movement, and was the first instance of “moving pictures.”

One of the earliest examples of modern animation can be seen in Winsor McCay’s Gertie the Dinosaur from 1914, an animated short created from hand-drawn sketches. This is also the earliest example of keyframing and animation loops. It wasn’t until 1937 that the first animated feature film was released: Walt Disney Studios’ Snow White and the Seven Dwarfs.

The first example of computer animation came nearly 50 years later, born from experiments in computer graphics for science and research purposes. It can be seen in the opening sequence of Alfred Hitchcock’s 1958 film Vertigo. Here, a WWII anti-aircraft targeting computer called “The M5 gun director” was used, along with graphic cels and a pendulum to generate the endless spirals that the film is noted for.

3D animation techniques quickly evolved, with the first realistic computer animation coming in 1961. Created by the Swedish Royal Institute of Technology on the BESK computer, it’s a 30-second vector animation of a car traveling down a highway. The first human figure computer animation, Computer Ballet, came just four years later in 1965, using computer-generated stereographic 3D

Frame-by-frame animation

The oldest form of animation, frame-by-frame animation is any form of animation that is shot one frame at a time, like a flipbook. It is usually reserved for non-digital animation such as hand-drawn or stop motion animation.

Motion capture (mocap) animation

Motion capture uses a mix of technology and mocap sensors to track and record real-life movement, and translate it into 3D animation. Mocap devices, made up of sensors and markers, are attached to an object or actor, which are then filmed on a special camera rig.

Procedural animation

Procedural animation automatically generates animation in real-time. This is different from mocap and other 3D animation where animations are predefined assets (i.e., they have been created by hand or with a mocap device). The technique for procedural animation is to generate animations that are reliant on physics simulations like water, for example, where the simulation would take fluid dynamics into account.

Behavioral animation

Behavioral animation is a form of procedural animation where an autonomous character can determine its own actions to an extent. It relies on generation using certain rules that define how objects react to their environment. It can be used to animate crowds or flocks of animals, using relatively simple rule-based motion for a large number of moving objects.

Keyframing

Keyframing is the backbone of animating any form of movement, creating a smooth transition between frames. Digital keyframe animation identifies different elements in each frame, and chooses how those elements will move over time (frames per second) for the most natural result. You can adjust your keyframes using different parameters like position, scale, rotation, and opacity, and also the manner in which you want the action to be performed. This is called keyframe interpolation.

Physically based dynamics

In computer graphics, physically based dynamics is concerned with the simulation of often complex physically plausible behaviors. This form of animation is popular in video games, movies, and interactive simulations. These animations are created in physics engines where physical behaviors can be scripted, even those with minute details such as fluids or smoke.

Morphing

Morphing is a visual effects technique where one object seamlessly transforms into another. This is different from tweening, which inserts images between keyframes as an animation effect to create the illusion of movement.

2D animation

A traditional form of animation, 2D animation creates movement in a two-dimensional space. It occurs when slightly different drawings are sequenced together over time (typically at 24 frames per second), giving the illusion of movement, but with no depth to the image. This is most commonly used for cartoons.

3D animation

Created using software, 3D animation takes computer-generated objects and creates the illusion of movement through a digital three-dimensional space. Unlike 2D animation, you don’t need to animate every frame. 3D animation is split into three parts: modeling, layout and animation, and rendering.

Animation is a constantly evolving field. In just one generation, we have gone from watching movies and playing video games in 2D, to 3D, to virtual and augmented reality. Increasingly realistic and immersive animations are becoming possible with advances in computer graphics, software, and hardware, in part driven by increasing demands for higher-quality content.

To meet this demand, animators are moving towards procedural workflows by working in game engines, where animation can be mixed with computer graphics. This gives more control, and the ability to create and collaborate in real-time. These workflows are also enhanced by advances in machine learning, which automates a lot of previously manual work.

It also means that animators are no longer siloed. The same techniques, workflows, and software can be used across film, video games, advertising, virtual reality, architectural visualization, and much more.