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Visualizing SIGGRAPH

Wayne Holder, San Diego Professional Chapter, ACM SIGGRAPH

My friend, Alan Scrivener, asked me to write an article about SIGGRAPH for the San Diego chapter. As an incentive, he offered up a press pass to the 2001 conference in Los Angeles and further offered that I could write anything I wanted about the conference. Having never attended the full conference before, to say that I jumped at the chance would be dignifying my response. I jumped on the chance like it was the only remaining bowl of cocktail shrimp at a product intro reception. It wasn't until later that I started to wonder just exactly what I would write about.

While I've followed the growth of SIGGRAPH over the years, and marveled at all the advances that have been heralded there, I didn't feel it was fair of me to try and masquerade as a journalist when it came time to write my article. So, I simply decided that my contribution would be to simply write about how attending SIGGRAPH 2001 and getting a chance to gawk at all the bright, shiny bits of knowledge and technical prowess on display there had inspired me. So, with that disclaimer out of the way, here's my version of "How I spent my summer vacation at SIGGRAPH."

What is SIGGRAPH?

In my opinion, it might be a more difficult task to try and say just what a SIGGRAPH conference is (especially to all people) than to write a complete summary of everything that happened there. I say this mostly because, among my friends and colleagues, the SIGGRAPH conference is said to have an almost mystical quality that draws people back year after year. On the surface, of course, a SIGGRAPH might seem like a Comdex, or any other large trade show that displays vendor's products and hosts presentations by a variety of speakers. However, even to my limited experience in attending SIGGRAPH conferences, I think this really misses the mark. SIGGRAPH does have some mystical effect on many people who attend it, I believe, and this is the main theme I'm going to try and explore in this article. Just give this mystical effect a name I'm going to call it the SIGGRAPH Effect.

Can Attending SIGGRAPH Make You Smarter?

Another friend of mine, Will Ackel, has maintained for years that he actually feels smarter while he's attending a SIGGRAPH conference. If so, this could be a useful spin-off of the SIGGRAPH Effect. Several other people I asked about this claimed to have experienced a similar effect, although for some the sensation was venue specific. For example, some told me that just having a chance to mingle with such a large collection of exceptionally smart people gave them a contact high, of sorts. Others told me that sitting in the dark at the Electronic Theatre, their brains locked in sync with the most technically sophisticated set of visual artists and technical literati likely ever to sit in one place in the course of a given year, gave them a similar rush. I can confirm that I personally experienced both of these effects at the 2001 conference.

Of the two, I found my experience in the Electronic Theatre to be the most intense. However, I'm not sure that the effect comes from the show itself, as I would venture to guess that I might have experienced 95% of the effect even if I'd sat through the whole show with my eyes closed. If you've never been to the Electronic Theatre, let me explain why I think this is so. First, the Electronic Theatre is not simply a Film and Video show, although it presents some of the best work you're ever likely to see in one venue. No, the Electronic Theatre is partly a spiritual pilgrimage and partly a visual and aural feast. It's a little like coming home after a long, tiring journey to find your home filled with all your closest friends who usher you into the dining room where there is a table set with all sort of fabulous food and drink.

The Journey is the Reward

For me, the journey home started outside in an immense queue of people waiting for buses to take them to the show. Perhaps in any other line of this sort you'd find a collection of restless, slightly unruly people all angling to better their place in the queue. But, no, this is a SIGGRAPH event and even waiting is something to appreciate and savor. I note that the people standing in front of me are engaged in an enthusiastic discussion about visual arts techniques. Even though I consider myself fairly up to date on computer graphics, I don't immediately grasp what they're talking about. But then, before I can dwell on this, my aural receptors lock onto another conversation happening just behind me. I can follow this conversation better, as it's about special effects in recent films, but just as I'm about to join in and inject my own opinions, my eyes seem to do a spontaneous panning zoom (you know, the vertigo-like effect where the camera quickly pulls back while simultaneously zooming to keep the subject the same size) and it feels as if I'm suddenly able to comprehend the hundreds, if not thousands of such conversations happening all around me. This was my first contact high at SIGGRAPH 2001.

However, before I can fully appreciate this magical effect, my friend Alan arrives and breaks me out of my semi-trance. We compare notes about what we've seen so far and lapse into our usual conversation about all things cosmic and meaningful, but the contact high persists and I start to feel a growing sense of anticipation, much as I imagine the crowd in line is feeling. Then, suddenly, a stream buses flow past and start loading people at the head of the line. The crowd around me barely reacts but, soon, the line starts to ooze forward and Alan and I ooze along, too. The whole process feels almost peacefully serene, but the beat of the crowd picks up as we get closer to the loading zone. Soon, we're on our bus and on the way and my contact high starts to fade, as if I required close proximity to the throng of waiting people waiting in the line to maintain it.

But, after arriving at the theatre, the sense of anticipation started to return as we filed into the auditorium. Perhaps it was the Old-LA feel of the Shrine Auditorium, or the slick, multi-screen layout the Electronic Theatre staff had setup, or perhaps it was just that this was the first time I'd been inside a venue that has hosted the Academy Awards, the Grammys and so many other awards shows, but within a few minutes I was starting to feel light headed again. Then, after a short delay to wait for all the buses to disgorge the rest of the audience and make their way to their seats, the show began. I suppose I could try and summarize what I saw and what I thought about it all with some sort of critical review, but the truth is I decided to just lean back and let it the light enter my eyes and bounce around inside my head. It was a great show. And, afterward, while making my way back to the bus for the trip back to the convention center (photo 1), I noticed that I had the slightest inkling that perhaps I did feel just a tiny bit smarter than I did before the whole experience.


photo 1

All Things Technical

Given that I had a full press pass, the one other thing that I wanted to do, besides spacing out at the Electronic Theatre, was to pick a single topic to explore in greater depth. This turned out to be a fairly easy choice, as one topic that, for purely personal reasons, has fascinated me for a long time is the technology needed for large scale digital projection of images. So, after reading over the description for course #35 ("The technology of digital cinema"), I knew I'd found my topic. And, as an added bonus, I noticed that one of the presenters, Charles Poynton, was a person I'd always wanted to meet and give a personal thank you, as his writings on color (and, in particular, his discussions of gamma) had been of immense help to be back when I was gainfully employed in the early computer game industry.

The course, it turned out, was being held in the University of Southern California's Digital Cinema Laboratory which has converted the old Pacific Theatre on Hollywood Boulevard (near Wilcox) into a state-of-the-art digital theatre. The location of the course meant another bus trip from the Los Angeles Convention Center but, as an extra bonus, by being exceptionally obsequious, I managed to wangle a behind-the-scenes tour of the projection room where I got to ogle the Texas Instruments' DLP-based projection head (photo 2), but more on this later.


photo 2

Walking into the theatre itself felt a little weird until I realized that, in this age of multiplex screens, it had been many years since I'd been inside the type of theatre I'd grown up as a boy watching films in. There was the same gentle slope of the auditorium's sea of uncomfortable, but classic-style seats that flowed down to the open space in front of the screen (none of the nose on the screen, layback seats here, thank you very much) along with the still slightly sticky feel on the bottom of my shoes as I inched into my chosen spot. But, once the course was underway, the interior style of the theatre couldn't have been more of a contrast with the presentation on just how far cinema has come in the digital age.

For me, the one speaker that seemed to put it all into perspective was Chuck Harrison of Far Field Associates, LLC who gave some nice comparisons on just what are the technical issues behind the push to replace mechanically projected film with microscopic arrays of mirrors or tricolor LCDs. In particular, Mr Harrison pointed out a few details on the apparent resolution of film, such as the tendency of the frames to jitter around in the gate and degrade the image quality as the sprocket holes in the film wear. He also had a nice live demo of Christmas tree lights set against a black velvet backdrop to make some points about contrast and apparent brightness that you just had to see to understand. I found it utterly fascinating.

It was also great to finally get a chance to see a demo comparing digitally-projected images to film. I can't say that there were any particular differences or advantages that jumped out at me, but the digitally projected sequences did seem exceptionally clean. On the negative side, though, I did notice that the flat-shaded areas of the one example of animation shown from "The Emperor's New Groove" exhibited a visible grid pattern. Note: asked about this during the Q&A session and the TI representative explained that it was due to the spacing between the micromirrors in the DLP system. However, the TI rep. noted that newer design for the micromirror array would not exhibit this defect. And, in fairness, had I not been looking at the screen with a very critical eye, I probably would not have noticed the effect at all.

In the Projection Booth

As I said before, by carefully stalking the course presenters I managed to get an invite, during the break for lunch, to peek behind the scenes and look over the various system components that made up the digital projection system. While the heart of the system is the DLP projection head shown in photo 2, there are two other important pieces to consider. The first, the light source for the system, is actually the same component used for a film-based system. In fact, the DLP head is designed to bolt into the same spot where a film head would go (photo 3 shows the film head used to project the film-based examples shown in the side-by-side comparison.) As these system are not cheap, and given the very cost-sensitive nature of the theatre operation business, I was told that this was a very important design consideration.


photo 3

The final component, and one which I had never heard discussed before attending this course, is the subsystem that feeds the image data to the projection head and the audio data to the theatre's sound system. If asked, I might have guess that this data stream would require perhaps hundreds of gigabytes to deliver a theatrical release. But, I was told that the small boxes shown in photo 4 (there are two nearly identical units in the picture, with one stacked on top of the other) requires only 5 or 6 DVDs to load it with a complete, cinema-quality movie. And, as you might expect, the whole load of data is fully encrypted and keyed to only play back one particular system. In fact, I understand that in a production system the data stays encrypted right into the projection head to prevent someone from tapping into the data stream, making a copy, and trying to play it back to the projection head later. I was even told that some digital projection system can modulate the projected image in a way that encodes a watermark that marks any attempt to make a pirate copy using a video camera or camcorder. Ah, the brave new world of digital rights management!


photo 4

Gizmos and Gadgets

While the course on digital cinema was the highlight of SIGGRAPH for me, I just had to saw a few words about the wonderous toys on display in the exhibits portion of the conference. I've attended quite a few trade shows in my 49 years, but nothing really measures up to the odd variety of strange gadgets you can find at SIGGRAPH. One general category of gadget that I find utterly fascinating are the printer-like devices that can convert digital data into a real 3D object. Of these, I particularly liked one that used a modified inkjet printer mechanism to craft obejcts, such as a functional ball bearing assembly out of corn starch and colored sugar water. Yup, you read that right, corn starch and sugar water! And, just for sheer visual appeal (and touch) check out the force-feedback haptic device being demoed in photo 5. When the holodeck finally arrives, I'm sure you'll be able to try it first at a future SIGGRAPH.


photo 5

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