My First Ray Traced Computer Graphic Christmas Card 1995

All these blog entries up till now have been leading up to my first real computer-generated Christmas card. This was the cover image on the card.

My 1995 Christmas Card Image

The card was printed on ordinary 8.5″ x 11″ paper one quarter size with a quarter inch margin. The page was then folded twice to make a 4.25″ x 5.5″ card. On the inside was the following message.

“Can it indeed be that
God dwells among men
on Earth?”

1 Kings 6:27

“And the Word became flesh
and made his dwelling
among us”

John 1:14

Merry Christmas and Happy New Year

This would be followed by my signature. I actually signed my name one time on a piece of paper, scanned it and turned it into an image which I cut and paste into Microsoft Word every Christmas card since then. So if you get a Christmas card from me in 2013 my signature will look exactly like it did in 1995 because it’s the same image.

The word “Emmanuel” is Hebrew for “God with us”.

While this image looks like a couple of angels in the foreground, the Star of Bethlehem high in the background, and Bethlehem itself on a distant horizon. It is in fact a clever bit of forced perspective. When creating models for ray tracing sometimes it’s important to model the objects at a particular size in order to get the proper lighting effects and texture effects. I also wanted to get the idea that the scene was being backlit by the Star. However with a bright light source in the distance casting shadows forward, the angels themselves were too dark. When I tried shining a light on the front, it illuminated the ground and the Town of Bethlehem too much. I actually ended up creating four spotlights with two each shining on the angels to illuminate them. But there’s more at work here. The “Little town of Bethlehem” is much littler than you think. It is actually a small model sitting in the foreground. Also the Star looks like it is distant with lens flare rays appearing in front of the other objects. In fact Star and the rays are a physical object in the foreground between the Bethlehem model and the angels. In the image below I’ve moved the camera back and up at a different angle to show you what the model really looks like. Sometimes when you’re trying to compose a good-looking image, you just have to fudge it.

The secrets behind the forced perspective in this image.

The secrets behind the forced perspective in this image.

We’ve not seen the last of St. Gabriel Angels. It will show up again in the 1996 Christmas card as a Christmas tree ornament. Stay tuned…

It All Started with the St. Gabriel Logo

Official logo of St. Gabriel Church Indianapolis originally designed by parishioner artist Joanne Austell

Continuing with my saga of computer generated Christmas cards, before we get into the first card I want to tell you about my ray traced version of the St. Gabriel the Archangel Catholic Church logo. Shown here on the right.

The image was designed by St. Gabriel parishioner and artist Joanne Austell to commemorate the 25th anniversary of the founding of our parish on the northwest side of Indianapolis. I’d always been a big fan of the image and I promoted it and used it wherever I could especially when designing the website for the parish. I wanted to create a three-dimensional looking version of this elegant 2-D line drawing.

The image below is what I came up with. I actually do a very good job of re-creating it to the extent I had hoped. When I was working on it I didn’t have a copy of the logo handy at the time. Somehow I thought original line drawing had a nose on it. I remember it had a very distinctive shape and I spent a lot of time trying to re-create that contour. Unfortunately the contour was remembering was actually the chin of the original drawing. By the time I had completed the image and realized my mistake I had already gotten used to seeing the nose on my version so I kept it. My image actually has no chin at all. I spent a lot of time trying to get the sweep the arms just right. I never was completely satisfied with that but at least it’s closer to the original than the face was.

This angel image would be reused in my 1995 Christmas card as well as several other cards. It also was the basis for this style of all the figures used in subsequent cards. So if I’m going to tell the story of how I created all of those Christmas cards we really needed to show this one first even though it wasn’t a Christmas card.

You can click on the image for a larger version.

At one point I had created detailed video explaining the mathematical formulas behind the various shapes and a sort of step-by-step visual explanation of how I pieced together the geometric shapes to create the image. Unfortunately I never completed the video and part of the files I used to make it (most notably the open captions and the voiceover narration) somehow got lost. I’m going to go back and re-create that video someday but for now you can just enjoy the still picture.

In the next installment we finally get to my 1995 Christmas card.

My First “Computer-Generated” Christmas Card (circa 1976)

Starting in 1995 I begin making Christmas cards using the Persistence of Vision Ray Tracer (POV-Ray) open-source freeware software which I helped create. Using a script of text commands it generates photorealistic three-dimensional images with realistic lighting, shading, shadows and other image effects. I’m going to use this blog to share some of my creations throughout the years however before I start off with the 1995 card, I thought it was important to share with you my very first “computer-generated” Christmas card.

It consisted of some ASCII art spelling out the words “Merry Christmas” followed by a cheesy bit of verse that I composed. The entire thing was printed out on green bar computer pape line printer of the DEC-System-10 computer at IUPUI when I was a computer science student there. An image of the card is shown below but in case you can’t read it, following that is the verse that I wrote (questionably bad punctuation included).

My First “Computer-Generated” Christmas Card

MAY YOUR BIAS VOLTAGE BE EQUALIZED,
AND ALL OF YOUR DIODES GLOW.
MAY ALL YOUR CAPACITORS KEEP THEIR CHARGES,
AND NONE OF YOUR FUSES BLOW.

MAY YOUR PARITY ERRORS BE VERY RARE,
AND YOUR DOWNTIME BE QUITE SHORT.
MAKE YOUR REGISTERS NEVER OVERFLOW,
AND NONE OF YOUR PROGRAMS ABORT.

MAY CHRISTMAS BE AS HAPPY FOR YOU
AS IT WILL BE FOR ME.
THE REASON MINE WILL BE SO NICE
IS I'M PRINTING THIS GREETING FOR FREE.

NOW IF YOU THINK MY CHRISTMAS VERSE
SHOULD BE WITTIER AND CUTER
I HAVE TO SAY "THAT'S NOT MY JOB!
GO BLAME IT ON THE COMPUTER."

     IN OTHER WORDS, A VERY MERRY CHRISTMAS AND
      THE HAPPIEST OF NEW YEARS FROM –-

          CHRIS YOUNG
          AND THE IUPUI DECSYSTEM-10

Here are some of the obscure references behind the text.

“Bias voltage” is something that tape recorders use to eliminate background hiss and noise. Rather than having the electricity go plus or minus a couple of volts say from +2v to -2v the recording head adds a bias so that perhaps it goes from +5v to +1v. I don’t know if these values are even in the ballpark of what’s actually used I’m just explaining the principle. In the mid-1970s cassette tapes came in different varieties. The ordinary tapes used “normal bias” and the newfangled metal oxide tapes use something called “high bias”. When you play back the tape, in order to get the best results your playback had to equalize the bias voltage properly. There was little switch you had to throw between high bias and normal bias. I still don’t understand completely what it means but it sounded cool so I included it.

“Diodes glow” in the mid-70s light emitting diodes were relatively new technology.

Capacitors and fuses are pretty straightforward. No explanation needed.

“Parity errors” when computers transmit data over a serial line they generally transmit eight bits at a time but in order to detect mistakes they transfer a ninth bit called a “parity bit”. Parity can be “odd” or “even”. That means in the string of 1s and 0s you add up the number of 1s and see whether you get an odd or even number. If you’re expecting odd and you get even that’s called a parity error. That’s bad news. You want them to be “very rare”.

“Register overflow” computers do arithmetic in special storage places called “registers”. But registers can only store a number with so many digits (or bits). If you try to do arithmetic with two big of a number you get a register overflow error. That’s bad.

“Programs abort” anytime a program stops unexpectedly is called an aborted program. (Bad joke from the archives… I’ve got one of those new “RU-486” CPUs and it’s causing my programs to abort.) ((Explanation of the explanation… Intel made a processor called a 486. However RU-486 was the name of an early “morning after” abortion pill.))

“Free printing” if I had typed up the text and taken it to the library and xeroxed it it would have cost me 10 cents per page. But if I typed it into the computer and told them to print me 30 copies of it, it was free. I had a psychology professor who had discovered this and rather than type up his class notes or handouts and xerox them, he would just put them on the computer. They would print as many copies as he needed to distribute to his students for free. It seemed strange to get class notes from a liberal arts teacher on green bar computer paper but it was pretty smart of him. It inspired me to print these cards that way.

“That’s not my job!” There was a popular TV show called “Chico and the Man” starring the late Freddie Prinze Sr. He was a bright and rising young Chicano standup comic who at the age of about 19 got his own sitcom. He played Chico who worked in an auto repair shop run by cranky old man played by the late great Jack Albertson. Although he talked in plain English most of the time, whenever “the man” would tell “Chico” to do something he didn’t want to do he would throw on a very thick Hispanic accent and say “ezz no my chob mhan”. (It’s not my job). That phrase got to be a pop-culture catchphrase. Tragically Freddie Prinze committed suicide at age 22. He was the father of TV and film star Freddie Prinze Jr.

“Blame it on the computer” is to this day a pop-culture catchphrase.

Fractal Valentine

I thought I would kick off my graphics blog on Valentine’s Day with one of my favorite images. This fractal Valentine contains 2327 individual harts of seven different sizes.

From Ray tracing

I will add more details about this image later. I just wanted to get it posted quickly for Valentine’s Day.

My Fascination with Graphics

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When I first got involved with computers, one of the things that most intrigued me was the use of computers to generate art. Having very little physical ability and eventually losing the use of my hands completely, traditional artistic media were beyond my grasp. But like many aspects of my life, technology comes to the rescue and allows me to do things that would not otherwise be able to do. Computer graphics gives me the opportunity to express myself artistically despite my severe disability.

In the late 1980s I got involved with an online project called the Persistence of Vision Ray Tracer or POV-Ray for short. I began contributing code to this open-source freeware program that allows you to create photorealistic images using nothing but a text language and a lot of computing power. Eventually I became the team manager for the POV-Team and even published two editions of the book entitled “Ray-Tracing Creations” which sold several thousand copies but is long out of print.

In 1995 I created my first Christmas card using my ray-traced computer-generated artwork. I’ve created a new image every year since then as well as used ray tracing for other graphics projects. In this blog I plan to share my images as well as explanations of how my artwork is created. Some of it will be articles about how they were created and others will be video demonstrations.