The problem is that this is an exponential process: It might take you just a few seconds to get a picture that’s good enough to get a feeling whether the animation works. Perhaps after an hour it looks pretty good or after a few hours it starts looking very good. But if you’re aiming for perfection, you’ll be running the poor farm of rendering computers ragged for ages.
We could play the vinyl version of the movie, with a little bit of grain, or we can get you the CD.
So the technical team decided to try an experiment. What if they rendered the same scene with different durations of rendering time, getting various amounts of grain, and then see what actually looked best? Ultimately, the feel of the film was going to be a subjective decision, and obviously, if the director insisted on near perfection, that would potentially mean putting the film’s release date back, or sending someone to the nearest RadioShack to buy another load of servers.
“Our director of photography, Ian Megibben, had a great idea,” Halstead recalls with a smile. “The director loves music. He loves playing music. He loves listening to music. We figured that perhaps the best way to pitch this was to say that we could play the vinyl version of the movie, with a little bit of grain, or we can get him the CD.”
The screening room must have been holding their breaths; if the decision would be to get the film as clean as possible, it would have had tremendous financial and timeline implications. But luckily writer Andrew Stanton chose to embrace a bit of grain, preferring the look of the movie that hadn’t been rendered to computer-enhanced perfection.
The movie that takes 1,800 years to render
Even with a bit of grain, “Finding Dory” wasn’t a lightweight. The average render time on the movie was around 53 hours. On average. For every single frame in the movie, rendered out in the final 2K resolution needed to show the film in cinemas.
“We had some frames that were pretty fast compared to 53 hours,” says Halstead, “but we also had scenes where there was so much going on that it took 10 times more — 500 hours or more to render a single frame.”
In “Finding Dory” there are 24 frames per second, 60 seconds per minute, 102 minutes in the film. And there are two cameras to render, because the film is in 3D. If we’ve done the math right, that means you’re talking about a render time of, oh, 1,800 years, give or take.
Of course, you can parallelize a lot of that; if you are rendering on a high-end, 16-core gaming rig with a ton of RAM, you might be able to get that time down to just a century or so. Eager as we are to see “Dory,” I’m pretty sure few of us would be willing to wait a few hundred years to enjoy the film, so it’s a good thing Pixar has a pretty beefy rendering farm.