Science Dimension volume 3 issue 5 October 1971
|Above: Nestor Burtnyk, and engineer in NRC's Radio and Electrical Engineering Division, uses the Data Systems Section computer graphics facility to develop some of the images which appear on the cover of this issue of Science Dimension. (NRC)|
"Fine art," wrote the British art critic John Ruskin more than a century ago, "is that in which the hand, the head, and the heart of man go together." Add to that the computer and a whole new avenue of expression is born.
The production of a work of art - be it music, painting, films, or what not - consists of translating an idea into a description or set of instructions and then translating the instructions into the final embodiment. Similarly for film animation.
The animator puts his ideas into thousands of small drawings, which by means of slight progressive changes, are used to simulate motion in the animated film. Throughout the years, this area of film production has been both laborious and time-consuming, as well as extremely expensive.
Now the National Research Council of Canada has developed techniques which will enable the professional animator to use the computer to assist him in his creative work, provide him with a new means of expression and reduce the time required at the drawing board.
Computer assistance in animation is inaccessible to most animators because of communication difficulties. The NRC system is one of the few being developed for the use of professional animators.
Since an animator's ideas involve mainly pictures and their motion, it is appropriate that the communication of ideas between him and the computer should be largely through pictures. Through the use of NRC's interactive computer-controlled graphic system, the animator can develop pictorial sequences directly on the cathode ray tube display without having any knowledge of computer programming.
"Most potential users of computers," say Nestor Burtnyk and Dr. Marceli Wein of the Data Systems Section of NRC's Radio and Electrical Engineering Division, "are not particularly interested in programming, but they are interested in solving a problem. For them, the important thing is to be able to communicate freely with the computer in a way that is meaningful to them and relevant to their problem."
What the animator wants, they say, is a facility where he can do the kind of operation he wants to do. He doesn't have to have any knowledge of how the computer is programmed because the programs that provide him with this facility have been written by someone who understands computer programming.
A package of three-dimensional drawing and manipulating programs developed by NRC allows the animator to work with the computer. The animator sits at a display console with a cathode ray tube display, which is very much like a television set. He is provided with a variety of input and control devices such as keyboard buttons, knobs, thumbwheel encoders, a light pen and a hand-held positioner called a "mouse." With these devices, he draws and manipulates pictures in three dimensions directly on the display screen. A number of separate picture components, each capable of independent motion, may be manipulated separately as desired and then combined to form a composite picture.
A group of supporting graphic programs complements the 3D graphic package. A free-form sketching program allows the animator to create free-hand drawings. Other programs operating in conjunction with the package allow distortion by modification of picture components. Using the "mouse" to control position, the coordinates of selected points may be changed in any direction. In addition, selected parts of an image can be distorted by shaping. The animator therefore has available to him a greater freedom of choice and expression.
"The animator is attracted to the computer," says animator Pierre Moretti of the National Film Board, Montreal, "because it is able to handle complex visual structures that would involve a tremendous amount of handwork or which would be impossible to handle by conventional methods. In addition, viewing a sequence as it is being done can save the animator time since he doesn't have to wait for laboratory processing to evaluate his work. The hope of lessening the amount of tedious work involved in animation is very interesting to us."
A few years ago when it was necessary to rely on elaborate programming in order to work with the computer, it was mostly intriguing to the animator. However, since interactive systems have been developed, there no longer is any doubt that the computer is useful to the animator.
"'The use of this new tool," says Mr. Moretti, "may lead us to discovering new approaches to animation."
The technique of key-frame animation used in the NRC system involves the creation by the animator of isolated frames at key intervals during a sequence, with the in-between frames to be computed by interpolation. Since the pictorial content of successive key frames need not bear any particular relation to one another, a wide variety of transformations is easily produced.
|Above: Selected frames of a walk sequence. There are five key frames per cycle of the walk. Each key frame consists of three cels. (NRC)|
Starting with a script and a story board, the series of key sketches that will progressively depict the action must be planned. These keys will include the extremes of all movements, since they will be used as the terminal points for interpolating the in-between frames. Once all the key frames have been established, the animator can begin preparing his picture components or cells by sketching the images directly on the display. As these picture cels are created, they are saved in the disc library for use at a later time. Each picture cel is interpreted as a 3D shape that may be scaled, rotated, and positioned as required. A composite cel for a key frame may be assembled by overlaying a number of individual picture cels. Pictures for subsequent key frames may be partially or completely redrawn, or alternately, may be derived by modification of existing pictures using one of the distortion routines.
The Data Systems Section, in collaboration with the National Film Board, already has made an experimental film which was shown at a conference of the Society of Motion Picture and Television Engineers held in New York last October. NFB also has started work on a program of computerized animation films and expects to have its first 10-minute film ready some time this year.
|Above: Children of the World - A promotional sequence, designed by Philip Quan from the CBC Graphics Department for a Network Special. Two excerpts are shown here. (CBC)|
"Visiting artists," say Mr. Burtnyk and Dr. Wein, "are encouraged to experiment with our facility in order to help assess its usefulness in their creative work. So far their adjustment to this new medium has been generally favorable."
Will the computer replace the animator?
"The most important function of the animator," says Pierre Moretti, "is to create or to invent ideas - not to make thousands of drawings. I don't think the computer will have this type of imagination for some time - if ever!"
Reprinted courtesy of the National Research Council of Canada