Often, timing prevents Pixar from taking advantage of the RenderMan Group's latest code. Its next movie, Up, is a case in point.

Dana Batali, director of RenderMan Product Development observes, "Ed Catmull has led RenderMan development to focus on one problem -- film-quality photorealistic rendering. We don't get sucked into real-time game visualization or architectural visualization or lots of many other interesting problems. In the long run, RenderMan probably isn't the largest money-making renderer. You could say that the Quake [game engine] might be. And the NVIDIA graphics cards are another take on this. At any one moment you can choose from probably 10 renderers -- there are many out there for people to choose. It's just that the larger facilities have come to realize that our commitment to the film-quality market, and the investment that Pixar makes in rendering technology, and the connections to ground-breaking facilities means that if you want to pick a renderer not just for today, but for five years from now, it would be silly not to consider RenderMan.

"I think there's a trend right now where people are realizing that they can get certain portions of the rendering job done in different ways than with a single RenderMan pipeline. They can get cheaper renderers -- or free renderers -- to do depth passes for example. And if they're RenderMan-compliant it makes it much easier to have a heterogeneous collection of rendering capabilities in their production pipeline."

The Polar Express is an example of a non-Pixar title that used RenderMan. © 2004 Warner Bros. Ent.

Batali makes a point of mentioning that some confusion exists with respect to the term RenderMan itself. "It's a mixture of a brand and an interface. In 1988, when the term RenderMan was coined, it was also our renderer at the time. Rob Cook and Loren Carpenter had produced the REYES (Renders Everything You Ever Saw) scanline rendering algorithm. There were no other renderers at the time that understood the interface. But it's only one small part of the larger puzzle. The larger puzzle includes the REYES algorithm and motion blur. Motion blur was an important feature. You wouldn't care about that particular effect in architectural visualization, for example. It's only the folks who look at pristine-quality film who try to make sure that you don't get a headache when you watch movie images. But you can have a RenderMan interface renderer that doesn't have motion blur. There's nothing illegal about doing that!"

Batali notes, however, that using a heterogeneous collection of renderers has its downside. "The more pieces you have, the more pieces can break. You have more complexity in your pipeline. Truly, there are some instances where it seems unwise to pay for a full-on RenderMan license. A graphics card might be able to do it, and do it faster. These are the kinds of things that people are dabbling with. But I don't think anyone can point to a world-shifting success story in that way."

One of the ironies of RenderMan's evolution is that the multi-year production schedules of Pixar's animated features sometimes have prevented the studio from taking advantage of the RenderMan Group's latest code because productions can't change software in midstream. Pixar's next movie, Up -- from Monsters, Inc. director Pete Docter -- is a case in point. As Batali observes, "It's frustrating for those production people, and for us, because when we have some cool new thing, we can't get them to test it. So it might go out with more bugs in it."

"But the good news," he notes, "is that with lots of different customers there's always someone starting a new production." So the visual effects studios, with their ever-shrinking schedules, are ideal test beds for new RenderMan features. Batali has watched this happen for two decades, having been involved with RenderMan since its inception. Lately he's witnessed some exceptional fluidity in the use of RenderMan for visual effects. "Some facilities, like Weta, don't lock down on a rendering version. They have a fairly sophisticated way -- on a per-shot basis -- to assign a toolset to any given shot or artist. They've made the strategic choice that if a new version of a tool, late in the game, offers some incredible possibility, they'll take advantage of it. As long as they can limit the risk to the place where that will potentially bring value, they have an important tool in their arsenal that other facilities may not have."