3D

Note: The animations have been converted from the Video Genie HiRes pixel by pixel so the aspect is wrong; on the Video Genie these images were approximately square in aspect. The screen was 384 by 192 pixels, so the images were also a bit larger than what you see on a modern computer. All the other images have been converted from screen-prints and those from the Video Genie have been adjusted so that the aspect is as it was.

It started, in 1980 when I first got my hands on a computer. With trigonometric functions I made axonometric projections or ISO. These were only seemingly 3D, not based on real models. I devised a simple method of applying hidden lines. These first programs were in BASIC and ran on a NORD10 (Norsk Data) mini-machine at the school (where I went to become an electronics engineer) the output was on a tektronix terminal (or plotter). It took several minutes to generate a picture. Here are two examples scanned from screen-prints from the tektronix (unfortunately the thermo-paper is steadily getting more brown).

These axonometric projections were fun but I soon realized that they had limited potential to make lifelike pictures, there were something missing. So I devised formulas based on angles in real 3D and ended up with a lot of trigonometry. Doing sin, cos or tan was real slow so I discarded these formulas before putting them to use and went for vector math.

I created myself a model based on me sitting half a meter away from the screen looking at an object through the screen as if the screen was a window. This screen was of course a flat plane in space based on the "looking at" and "down" vectors. The vector based formulas became very simple to compute, and without the trigonometric functions it was much faster. The hidden lines bussiness became a bit more difficult but, by expanding the original scheeme a bit, it still worked. The first images came from models of the all the basic polyhedron. Actually the tetraeder was not very spectacular so it never got saved even. I then made the more spectacular mathematical function representation, f.ex. sin(r)/r the one in the animations on the top and below.

The gif animations on this page are reproductions of Video Genie HIRES programs. Note: the aspect in the gif animations are wrong. I made them sometime early 1983, just before I had floppy-drives so it was cassette based. There was a basic program that would generate each frame and save them to cassette. This data would then be merged and an optimized assembly program would display the data. I had never seen anything like this and the sense of 3D was stunning the first time I saw it, it was so real and no trick. Here are two avi's made with the HT1080Z emulator. They are just like the real thing.