Graphics and multimedia: Computer animation programs

Computer animation programs

Computer animation, using packages such as Autodesk's Animator, is becoming popular for creating presentations and demonstrations. By linking the computer with video equipment (see below), video images can be incorporated. The final output can be displayed on the computer's monitor in the normal way, or else converted to a video signal and recorded on video tape for playback on an ordinary video recorder.

In essence, an animation package such as Autodesk's Animator (Figure 7.5) is a painting program with animation features, with facilities which include the ability to take in and edit video pictures. You create a series of still images, called frames, link them in an animated sequence called a flic, and combine flies to produce a presentation.

Animator allows you to create five types of animation:

• Cel animation, i.e. Disney-style frame-by-frame anima­tion of a series of individually-created frames.

• Fly-by optical effects, i.e. animating the movement of a piece of text or other image from one location and orientation on the screen to another by automatically generating the intermediate positions and orientations.

• Polymorphic tweening, i.e. turning one shape into another by automatically generating intermediate frames.

• Titling animation to scroll text in any direction.

• Colour cycling allowing you to automatically cycle

through a range of colours over a sequence of frames.

To facilitate this, Animator provides 22 painting and ani­mation 'tools', ranging from simple tools such as Box (to draw a box) and Circle (to draw a circle) to highly sophisti­cated tools such as Tween (to generate polymorphic tween­ing between a start position and shape and an end position and shape).

Multimedia applications

Multimedia refers to the convergence of audio, video, and other technologies with computer technology. As explained in Chapter 1, this convergence is facilitated by the trend towards the digitization of all forms of information, including digital audio systems, digital TV, and so on. By harness­ing the computer to these various media technologies, powerful training, entertainment, and presentation systems can be created. They are described in the remaining sections of this chapter.

Figure 7.5 An Autodesk Animator screen

Multimedia applications often involve the use of the computer to control equipment such as videodisc players, and mixing the video images with the computer's own output. It also includes the use of the PC with equipment such as video cameras and microphones to capture and edit video and audio input. At present, the main multimedia technologies and applications are:

• Interactive video, used mainly for training.

• Computer animation, using products such as Autodesk's Animator (see above), incorporating video and audio material.

• The use of data compression techniques to greatly reduce the amount of disk space occupied by video and other images. Compression ratios of over 100:1 are possible.

Interactive video

Interactive video systems (IV) allow the viewer to control a video programme using a computer. In practice, this means that the computer and video output appear together on the screen, the computer output often taking the form of either questions on the video sequence just seen, or else a menu of choices for further sequences. The viewer makes his or her response by typing at the keyboard, and the computer acts on this to determine which sequences of the video programme are played next.

IV can be achieved by linking a modified home video recorder to a computer. However, videodisc is a much better medium, for reasons which are explained in the next section.

The main application of IV is in education and training.

The videodisc in this case will normally consist of many short sequences, each one lasting just a few minutes. The video is controlled by computer software in the form of a training package written using a special programming language called an authoring language. This software carries

out the following tasks:

• It controls the order in which the video sequences are to be played. This can be modified by the learner, either by selecting menu choices or through the way in which he or she responds to questions. A learner with difficult­ ies may be routed by the program through different sequences to a learner that answers the questions correctly.

• It displays questions on the screen to test the learner's understanding of the video sequence just seen.

• It matches the learner's response to a question against a number of possible responses that are stored in the program, and so marks it right or wrong.

• It provides feedback to the user, encouraging him in the case of correct answers and giving explanations in the case of incorrect answers.

• It keeps track of the learner's score for assessment purposes, and of the parts of the course that he or she found difficult.

IV has been found to be a very effective training tool. It has the following advantages over conventional training methods:

• Because the video sequences are interspersed with com­ puter question-and-answer sequences, the learner has to apply his learning at frequent and regular intervals, which helps him retain and understand the material.

• The computer gives immediate feedback when the learner has typed an answer, and provides remedial instruction in the case of wrong answers. This is highly motivating, as well as ensuring that the learner has understood each point.

• The learner's route through the material can be geared to his or her needs.

• Because an impersonal machine rather than a human tutor is assessing his work, the learner is less embar­rassed and demotivated by wrong answers.

• The material can be presented in a form which is visually attractive and stimulating.

Another major application of IV is point-of-sale (POS). Customers are able to quickly access video sequences on the products that interest them, or find out more about the services offered by a bank or other institution. IV has been successfully used in DHSS offices, where it allows clients to determine their rights and benefits without needing to speak with an official.