A Better Mousetrap: The CAESAR

The animator is seated at a control console; before him is a color cathode ray tube on which is displayed a cartoon character frozen in mid-step. The animator adjusts the controls, then depresses a button marked Animate. A smaller CRT flashes a response: Doing my thing. And an instant later, the cartoon figure walks across the screen, smiles at the animator, and tips his hat.

Until recently this scene would have been science fiction, but a computer-controlled device now exists which produces fully-articulated cartoon animation. Its function is described as Computer Animated Episodes using Single Axis Rotation -its builders call it CAESAR. CAESAR is far beyond the point of being a mere laboratory curiosity; it is a fully-operational tool producing animated films every day on a time- and cost-efficient basis. The implications of CAESAR for the art of animation are enormous.

CAESAR is a descendant of ANIMAC, the original animating computer designed by Lee Harrison and his associates at Computer Image Corporation. ANIMAC was an extremely resourceful, versatile, and impressive device. It could handle three-dimensional work as well as two. ANIMAC, as a prototype device, suggested other possibilities for computer animation, and led to the development of SCANIMATE. SCANIMATE computer animation is now a familiar sight to television viewers, although they may not be aware that the images they are watching are computer-produced. SCANIMATE does only limited character animation; its principal use is in plasticizing and metamorphizing images. But SCANIMATE led to CAESAR, and CAESAR does full character animation.

Figure 1 - A figure displayed within a television raster will follow the shape of the raster when the proper electronic signal is applied.

CAESAR and SCANIMATE are unique among the many designs of animating computers in that they are basically analog devices rather than digital. With a digital system the plotting and programming of a key frame may require days of calculation. Then to animate the sequence the digitally-generated display might require several seconds to paint each frame on the CRT from which it is recorded. Because the analog system is faster, it usually takes an experienced animator working with CAESAR longer to plan a storyboard than it does to animate the film.

What does the finished animation look like? It looks very much like conventional film animation, although most of the drudgery associated with the production of animation has been eliminated, so perhaps the animator is freer to be creative. The quality of the image is good since it is displayed on a high resolution, 945-line color television screen. The handling of characters is not yet equal to the best of Disney Studios, but it far surpasses that which is seen on Saturday morning TV.

Once you understand some of the basic processes of the system and know its capabilities, CAESAR's creative possibilities are apparent. At its most elementary level, CAESAR's operation is the re-shaping of a television raster, the white square which is displayed on the face of a cathode ray tube. By applying the proper electronic signals to the raster it is possible to cause it to bend, squash, stretch, turn, or grow larger or smaller If a cartoon figure is displayed within this raster, he will also bend, squash. etc. For example, if a delta wave is applied to the side of the raster, it will bend and the figure displayed on it will appear to bow. And CAESAR will remember that bend and will play it back to you. But this is only the beginning.

Now imagine that the raster is divided into seven sections, as if there were seven vertical rasters. Each of the seven may be controlled independently. Now picture the cartoon character broken up into seven parts, like cutting up a paper doll, and each part displayed within a separate raster. The head is in the first raster, an arm in the second, the body in the third, and so forth. Since the rasters can be individually controlled, the animator looks at this array of head, arms, etc., on the screen and by manipulating the controls positions all of the pieces until they are assembled correctly and are in position for his first frame of animation. He then stores this frame in CAESAR's memory and advances in time to a later instant in the ongoing action and manipulates the character into the position which he will assume in this second key frame. In the conventional animation it is the production of the many pieces of artwork necessary to connect the key frames which is most time-consuming-but CAESAR does this in seconds!

Figure 2a - By applying a sine wave to the cat's tail and pivoting the tail from its base, the tail could be made to switch from side to side behind the cat.

Figure 2b - Using the same artwork for the cat but applying different wave-forms, pivoting some of the parts, and adjusting the vertical and horizonal size produces an angry-looking cat.

Figure 2c - The cat does a take. Horizontal size is changed on most of the parts, and a high-frequency delta wave is applied to the tail.

Here is how a typical sequence might be animated: Say that the action is to be a Run cycle, a fast realistic run with the character's foot hitting the ground every third of a second. Since CAESAR calculates in video scanning rate, rather than movie sound speed, there are thirty frames per second. The animator instructs CAESAR to copy the character from frame one into frames ten and twenty. This will close the animation cycle. He then asks for frame ten to be displayed and alters the position of the character's arms and legs so they are correctly positioned for the middle stop of the run. Appropriate squash and stretch to add bounce to the run are set with horizonal size and vertical size controls. When the animator is satisfied with the appearance of the character in its key positions, he presses a button which tells CAESAR to animate the sequence. CAESAR provides all of the animation between the key frames, with accelerations and decelerations or any combination thereof as desired, and plays back the results in the time it takes to scan the magnetic memory.

CAESAR would be equally obliging if instructed to make the character move in apparent depth, fly through the air, change colors, disappear behind objects on a painted background, or conduct lip-sync dialog with a live actor. It could do all of these things simultaneously if the script required it. And since the actions are recorded in a magnetic memory, it is relatively simple to re-play the scene or any part of it and make additions or corrections of the action or timing as desired.

With conventional animation it is usually necessary to prepare hundreds upon hundreds of drawings which must be inked onto acetate cels and painted by hand to produce the film. With CAESAR, the artist's task is relatively simple. It is usually necessary to produce only a few pencil sketches of the character illustrating full-face, profile, and three-quarter view. These drawings are broken down into their various parts and are rendered as high-contrast negatives. The negatives are keyed for color using transparent grey overlays, and are input to CAESAR through a TV system. Backgrounds may consist of paintings, photographs, models, full-scale three-dimensional objects, or virtually anything which can be displayed in front of a color television camera.

Figure 3 - The animator usually needs to make only a few pencil sketches of the character showing him in typical poses.

Figure 4 - The sketch of the character is rendered as a high-contrast negative, with each of the parts distributed separately. Additional parts may be included, for example several heads to simplify major changes of position or expression.

Figure 5 - To animate a simple "run cycle" the animator merely manipulates the controls to establish the position of the character for frame One and frame Ten (frame Twenty is identical to frame One), then CAESAR animates the Inbetween eighteen frames. To extend the scene the cycle can be copied automatically as many times as required The squash and stretch are added by use of the vertical and horizonal controls. Acceleration and deceleration are computed and incorporated automatically if desired.

There are of course limitations to the present system. If additional characters are required, it is usually necessary to animate them separately and record them on videotape in successive passes. Rotation of characters requires additional artwork. Real-time inputs are possible, but are not the usual mode of operation. Direct film recording is also possible, but videotape is recommended, with later transfer to film if required.

Animation has been losing ground in recent years as the cost of handwork and drudgery has steadily risen. Studios have gone to Xerox inking or other photomechanical processes. Disney has gone to live-action films for its bread-and-butter. Hanna-Barbera continues with limited animation. And the Japanese studios dread the day that animators' wages go up. TV animation has succumbed to time and cost pressures to the extent that animators who work for TV call their shops sausage factories, because every episode of every show looks like every other.

CAESAR could be turned into a sausage machine, but this would be an unfortunate waste of potential. No creative animator desires that his work emerge as a bland stereotype, but too often he is caught in the middle, having to simplify his ideas and make artistic compromises just to stay on board the treadmill. It is to be hoped that CAESAR's facility in handling the routine, mechanical elements of the animation process will free the animator and encourage him to further explore the human, creative aspects of animation.

Until now the existence of CAESAR has been generally unknown to animators. SCANIMATE has been Computer Image's stock-in-trade, while CAESAR's development has received virtually no publicity. Computer Image is now extending its operations from its Denver home-office to form Image West in Los Angeles. CAESAR is about to land as a bombshell on the world of commercial cartoon animation, and the impact will produce profound changes both in its economics and in its consideration of this art.

CAESAR has been, in a way, like the flea on an elephant. For the flea, that elephant was the whole world. Then one day he realized he had the whole world by the scruff of the neck ... but the world didn't know it yet...