3D Computer Animation- a personal story

X,Y,Zee. 1,2,3Dee. Circa 1984. Geometric modeling with flat shaded rendering on a PC. Unheard of. Mainframe stuff. Nobody believed you.

I used a system called CubiComp PolyCad10. One light, no texture mapping, no reflectance mapping, no moving camera, no procedural modeling, no parent child hierarchy, no inverse kinetics, no facility for animating a model at all, no spline surfaces or cross sectional modeling, no interactive dragging. Dross DOS. Enter numbers <CR> key. The program could be run off a double density floppy disk in 512k of RAM on a 8MHz 286 if you had a maths co processor. It had an external frame buffer as large as the computer itself! That'll be $US20,000 bucks thanks.

Ah the CubiComp. As its name implies, it was great at making CUBIc forms which weren't very COMPlicated. But the thrill in creating your own little world beyond that fragile sheet of glass was absolute addiction. One didn't have much to play with... 750 polygons as I recall. Polygons! Ha.. the poly's are all gone more the like. It would take about 300 just to make a decent sphere that didn't look like a Buckmaster Fuller geodesic dome when you zoomed past it.

It was a real nuts and bolts under-the-bonnet kind of system. The nature of the input, logical, procedural thinking and the mental frame of mind this demanded, was a million miles removed from the fresh, spirited, spontaneous kind of output one struggled to attain. It was like playing a game of chess. A battle of wits which called upon one's ability to think through a problem, to invent a solution... to create illusion. Instructions to set up the world, to fix the direction of the single light source, to load in a geometry file. Program code for rotations and translations trying to imagine just which combination of degrees and world units to push and pull parts of your model around to create a character of weight and personality. Fifteen pages of code to make something walk and no real time feedback until you'd recorded it all to video tape.

It was also a rude awakening to integer mathematics, when each time you rotated your model, its vertices were rounded down to the nearest XYZ coordinate location. The thing actually shrunk and corrupted over time, like a red dwarf sun collapsing under its own weight destined eventually become a black hole, that would, I had no doubt, pull our own world in with it. I never did go that far but I'm sure plenty of 3D models have ended up in some other dimension, another parallel universe of geometric rejects. Perhaps Homer Simpson bumped into them. But I digress. Human cunning fought back. Read in the model afresh and rotate it only once, render it, then chuck the imperfect child away and repeat but rotate it further next time.

'Staff Playtime' accepted for screening at Siggraph 1986.

My drunken top-hatted wobbly toy reminded some of a certain Australian Governor General of the day. Checkerboard ground abounds. Gourad shading and a hand crafted shadow. See it wobble!

I remember being criticised for the checkerboard floors I'd use for my testing which were all the rage in crome and crystal-balled 3D animation at the time. But I'd built the macro to automatically make these checks myself. I could make as many as I wanted (well 750 at least) and as big as I wanted. As texture mapping was yet to make an appearance, one needed some kind of field as visual reference for camera moves, I explained, and checks were quick to render. Besides, the black ones weren't real. They were just holes. I'd made them out of virtual air and saved myself hundreds of polygons which I could use for my model. But these critics weren't 3D trekkers like me. They just didn't understand....

Heck, if I used a wide angle lens, my otherwise velvet black world looked as if it went all the way to a shimmering interlaced infinity some 32,000 world units distant - the resolution was that bad. There was no depth cueing but I discovered that if I made a graded background, dark at the top, light at the bottom, then rendered black checks over this, I could create the illusion of a surface that disappeared off into the gloom the further it got from the camera. I loved that system's bytes to bits.

We learnt to put chamfers on our models to catch the play of light. I figured out a way to fake convincing shadows that tied my models to their world. Put the camera on the same axis as the prime source of light. Adjust the focal length of the lens - a long focal length for a light source at infinity, the sun for example, a wide focal length for a light just out of shot. Tweak some settings to render the model from this position in silhouette. Delete the model from RAM but leave its image behind. Now tap your cursor around this shape to create a single polygon. Project this polygon onto the ground, attach it to the model, and hey presto, you have a mathematically correct shadow in perfect perspective.

The original CubiComp 'camera' was static. You typed in six numbers to get the view you wanted. Before a system upgrade came along to do the job, we wrote our own software that allowed us to animate the camera. We adapted it from one we had written to create smooth moves on a traditional rostrum animation camera. Yes we flew all around our models like drunken helicopter pilots on speed, careering up every orifice we could find to test our newly acquired dexterity in aviation. Our virtual camera had no dimension, no weight, no actuality, no integrity. It was a blowfly's view of the world. But we knew something about cutting and cinematic language and soon nausea and sheer boredom had us firmly grounded.

Being animators, we wanted to bring things to life that had weight, quirks, personality. We also wanted to tell stories in 3D land and not just fly around corporate logos. And so the battle began. The manual was solidly technical. There were no creative recipes to follow. No footprints in the sand. Here was a system that you had to figure out what to do with it (a bit like a pencil really) and nobody else in Australia had one. Pioneering days indeed.

'Creepy Spider' by brother John.
See it creep!

One day in executing a macro, cutting and pasting the standard header we used to set up our virtual world, we accidentally picked up the wrong geometry file for a set of movements that we wanted to test. We set the machine to wireframe record to video tape overnight, locked the studio door and went to bed while the elves and fairies did their stuff.

In the morning instead of the film school's sexy corporate star logo slowly pulsating in size with gentle sinusoidal fairing that we were expecting, to our astonishment, this green stick insect crawled up the inside of our video monitor, its sticky stick legs occasionally finding purchase behind the glass, then slipped back to try again. I stared at my brother, then stared back at the screen. We had created life itself! This creature had a tenacity all its own in its single minded struggle to climb that screen. The motion file was addressing points in the wrong model in a way that had no logical sense. Spooky, exhilarating! This led to a whole menagerie of limping, wobbling, club-footed experiments, or 'E-motionals', as John Bird was want to call them.

'Sea Anemones' a study in organic motion.
See them sway!

Analyse the movement that makes the thing you are trying to represent unique. Distill out the essence of its spirit. We made a shinny blue block of plastic ripple like water when a blue ball dropped into it. So what if the ripples were square. Surreal man. Photorealism it ain't, fascinating it is. We made a sheet of paper shuffle towards camera like a wombat. Celebrate the abstraction.

Gather together a collection of parts, make them move as if they belong to one another, and who cares if they are not even connected.

When texture mapping finally came along in the guise of a system upgrade called 'PictureMaker', we could at last grunge up our otherwise all-too-pristine world. The eye delights in detail and pattern. Dirty corners, rust, chipped paint. Keep it all to scale though - this is not toy town.

'Tin Man' Peg-legged, spring thighed. Ah the challenge! A study in connected parts and gravity. See it limp (or is that dance)!

 

 


© david.atkinson@rmit.edu.au
7 september 1998