Computer Animation – Assignment 1

Types and Techniques of Animation [P1]

Example of an animation with onion skinning in use. The older the frame, the more transparent it appears. Although popularised by the introduction of computers in animation, onion skinning can be used in hand-drawn cartoons too, by use of translucent paper.
"Onion skin". Licensed under Creative Commons Attribution-Share Alike 2.5 via Wikimedia Commons - link
Footage of a racing event, clipped to the shape of text, using masking.
Image from
Keyframes and 'tween frames in the CG animation application Cinema 4D. In this example, a cube's position on the y-axis is set to 0cm at frames 0 and 30, and to 250cm at frame 25. The three keyframes are all that are needed in order to animate the cube rising, then rapidly falling again, and the interpolation that Cinema 4D calculates for this movement is shown on the right. Looking at the graph, and given the frame number, one can see that it correlates with the value in the y-axis box below the 3D view.
The software also allows the animator to change this Bézier curve easily, without the need for more keyframes.
Image created by myself; see license.

Uses of Animation [P2]

Computer animation has many different applications, and can be easily adapted to suit its need. Some of the most common uses of animation are listed and summarised below.


Many of the adverts seen on television and in other media are computer generated. The freedom of computer animation allows businesses and marketing teams to create captivating worlds, scenes and characters. The cost of designing and rendering CG imagery was once extremely high, but has dropped rapidly to such an extent that animation is often a much cheaper route for studios to take. The internet also allows animators and designers from across the world to easily collaborate on a project when it's built digitally. 3D CGI animation is also used by technology manufacturers to showcase their products, negating the need for a physical studio or photographer. In the small window of 30 seconds, a story has to be told and an idea sold, and computer animation lets this happen.

Creative Arts

Animation is used extensively by artists. The medium of film and motion has always been popular, but now that anyone is able to create and share their own content using software and the internet, animations have become even more popular. Using software like Cinema 4D, Maya and 3DS Max, it's possible to create complex animations relatively easily using of keyframing, textures and advanced physics simulation. A new form of art has emerged and communities have been created centred around animation, sharing ideas that can be realised thanks to the vast range of opportunities that it presents. Although categorised here as entertainment, feature-length and short films are considered by many to be a form of art, with competitions and awards having been devised to showcase and celebrate the work of animators.


Film was revolutionised when the first feature-length computer-generated movies were released in cinemas. Notable examples of these films include Toy Story and Shrek, created by Pixar Animation and DreamWorks respectively. At a time when entire computational farms would render for months on end to create such a long piece, the concept of animation in cinema was unbelievable to many. Render farms operating on several thousand servers are now capable of rendering these projects in days or even hours. Farms are used to render many of the films shown in cinemas now, and rendering is almost always required for live-action cinematography too, as special effects, colour alterations and text sequences are applied in computer software.


Animation and computer graphics in general are used extensively in science. Calculations for complex particle-based systems and physics simulators often now take longer to compute and "bake" than to render to an image or film. Animation is also often used for public announcements on television or the internet. Public safety advertisements in print also often make use of computer generated imagery. Animations can also be used to explain scientific theory in research and to demonstrate products in industry. Public safety advertisements on television could potentially be created using techniques of animation.


Universities and scientific institutions are increasingly making use of computer programs in order to simulate different events for a number of reasons. For example, researchers have constructed huge sections of the universe digitally using particle simulation, allowing them to accurately predict the movement of planets, stars and entire galaxies over millions of years. Animations can also be used to show medical processes, for example, as is sometimes shown in dental practices. In cases of particularly advanced or pioneering treatments, animation could be used to show the patient exactly what operation they would be undergoing. This use of animation could also be considered educational.

Persistence of Vision [M1]

It was historically believed that when the human eye sees an image which is then processed by the brain, a remnant of it remains in the mind for a period of time after the subject has changed – estimated to be around one twenty-fifth of a second. It was thought that the persistence of vision effect led to the illusion of smooth motion we see when viewing animation and video; the perception of motion. Persistence of vision was considered something that happened in the eye, and perception of motion something that occurred as a result in the mind. The fact that animations are simply a series of frames played in quick succession, but that appear to show moving objects, was often used as an example of persistence of vision.

In the animated image above, the gap appears to be filled with a green blurred dot, like the pink dots, when a person stares at the centre cross for few seconds. This is an example of the phi phenomenon.
"Lilac-Chaser" (Original uploader TotoBaggins, later uploads by Howcheng). Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - link

When viewing moving objects in real life, motion blur is added to the images our eyes detect, making it easier for our minds to interpret what we're seeing. Without motion blur, moving objects in our vision would seemingly disappear and reappear as they moved, instead of gradually moving, and we would be less able to estimate the speed of moving objects. Some televisions are able to display video at a framerate of more than 120Hz, and motion designers usually add motion blur digitally before rendering clips in order to achieve the best results. In fact, if the content has not been processed by motion blurring algorithms, the video can give viewers headaches.

The discovery of the phenomenon of persistence of vision has been attributed to a number of people; most notably Lucretius, a Roman poet, and Peter Mark Roget. It has been scientifically decided that an animation shown at fewer than 16 frames per second is obviously an animation, and that most can clearly see the frame changes as they occur. This threshold is higher in cinema and on older televisions, as the screen is unable to remain lit between frame changes. Persistence of vision was believed to have helped make this momentary black image less noticeable when a video was played.

The theory of persistence of vision has been disproven since 1912, and the persistence of motion explained instead by the phi phenomenon and beta movement, which are often confused.


A photo of a phenakistoscope with thirteen frames of an animation depicting a couple dancing.
"Phenakistoscope 3g07690u". Licensed under Public domain via Wikimedia Commons - link

A number of devices have been created throughout history that claim to showcase the theory of persistence of vision. Some of the most popular are listed below.

Techniques and Use in Animation

An example of rotoscoping, using a picture of a woman in a car.
Image from