Saturday, May 12th, 2012 Posted by Jim Thacker

FMX 2012: The Hugo shot that nearly killed us

VFX supervisor Rob Legato (left, with Pixomondo’s Ben Grossmann) explores the Oscar-winning effects of Hugo.

In our next report from FMX 2012, we bring you a cautionary tale from the world of virtual production. A recurring theme of the show has been that realistic previz is both a blessing and a curse: a blessing, because it enables a director to see more precisely what a shot will look like when complete – and a curse, because the director can then hold the VFX crew to it. And as the session on the Oscar-winning visual effects of Hugo showed, a spur-of-the-minute decision during previz can have dreadful consequences later in production…

As speaker after speaker at FMX has pointed out, arbitrary decisions taken during previsualization can have important consequences later on in production – and nowhere was this clearer than in one of Wednesday’s highlights: Ben Grossmann and Rob Legato’s presentation on the visual effects of Martin Scorsese’s Hugo.

If you’ve seen the movie, you can’t fail to have been impressed by the opening shot, the camera swooping out of the Paris skies and down the length of a platform at Gare Montparnasse, the crowds parting elegantly in front of it. It has everything: a 75-second virtual camera move, a large-scale digital environment, the seamless integration of numerous live-action elements. Plus, it’s all done in stereo.

As Ben Grossmann, Pixomondo’s VFX supervisor on the movie points out: “A shot like this doesn’t render itself.” That’s something of an understatement. In fact, each iteration took 150,000 hours to complete. The studio calculated that if they’d rendered it on a single computer, Scorsese would have been 89 before it was done.
Hugo’s opening shot: a stunning piece of cinema – but one that almost drove its VFX crew to despair.

So what was the thing that caused the most stress on the shot? The thing that came closest to driving overall VFX supervisor Rob Legato to suicide? The detailed digital model of Paris, surely? Stitching the virtual camera move together? Maybe even the smoke that billows in front of the camera? Nope. In fact, it was the snow.

That’s right. The snow you only see in the first 40 seconds of the shot, and which you barely register is there. Rob Legato takes up the story:

The snow was an afterthought. The way the story originally happened was that it wasn’t going to start snowing until they start walking to the graveyard, [where] the tone of the movie changes. But when I was doing the previz, I threw some snow into the shot – just because it looked cool, and I wanted to show it to Marty [Scorsese], as a suggestion for the way we could open the movie.

It was the very first shot I prevized – literally done in the first week I was there – but as luck would have it, it wasn’t finished until the last hour of the last day. The shot shows up on Monday morning. In literally an hour, we have to hit the go button to film out to send out the movie. And Marty sits down rather calmly, having never seen the shot completed – I was pretty happy with it, because Jesus, it only made it by a squeak – and looks at it and said, ‘So anyhow. What’s with the snow? More snow. I need snow.’

What? What are you talking about? It has snow. ‘Nope. It’s not what you showed me.’ But what I showed you was just crappy snow we threw into the previz in Maya. ‘Well, whatever you showed me, I liked it.’

By now, the Pixomondo guys have been awake for 48 hours, more, we can’t reach them even if we’d wanted to. But I’d had an inkling about this, so I’d asked for a snow matte in 3D, and even though I haven’t had much sleep either, I say, as politely as possible: ‘Marty, go outside for 20 minutes.’ And I have Greg Fisher, the colorist, make the Baselight into a compositing tool. So now I have three or four layers of snow, and I’m really proud of myself, I’m waiting for that giant pat on the back I so richly deserve, and he says, ‘Better. But that’s not what you showed me. What are you going to do?’

I said, ‘Marty, maybe you should go out for some pizza.’

In the end, we added a total of eight layers of snow, and that’s what’s ultimately in the movie. And he just came in and sat down and said, ‘Yeah, that’s what’s you showed me. Good. So why were you holding back?’

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