Oz The Great And Powerful’s Scott Stokdyk On Sam Raimi’s Special Effects

Posted by June 26, 2013 Comment

oz great and powerful 3dIf you get the option, I’d strongly recommend seeing Sam Raimi‘s Oz the Great and Powerful in 3D. It’s one of the most impressive but also well-considered uses of the form so far.

You may recall that I spoke to Raimi at the time of the film’s theatrical release, and tried to dig deep into his choices about the film’s stereography. My goal was to address a lot of the scepticism that surrounds 3D, and I think Raimi helped illustrate, at the very, very least, that making his film this way was definitely not a simple cash-in.

As the film is now headed to UK DVD and Blu-ray – and Blu-ray 3D, which I would specifically recommend – I’ve taken the opportunity for a follow-up chat with Scott Stokdyk, the film’s visual effects supervisor.

Stokdyk and I talked about the film’s new and unusual ways of integrating CG characters into live performance, about some of the wonderfully convincing simulation work, about working with Sam and, yes, about the 3D.

Before you start, though, I should give you a very basic explanation of one element of 3D filmmaking, something that Stokdyk and I go on to discuss.

So. When you or I look at something, we converge our eyes on that subject. We turn them in and look at it, pointing both eyes at the same item.

In filmmaking, the 3D camera does the same. Depending on the angle of convergence between the two lenses, the 3D qualities of the image are altered. Most basically, by selecting their convergence accordingly the filmmakers can make an image appear closer or further away, on this side of the screen or the other. This can remain constant throughout a shot, or be altered.

Or filmmakers can shoot a film with the two lenses set straight, directly parallel, and then overlap the image by different amounts in post production – effectively getting the effects of convergence later, in a way that’s easier to alter during editing.

Expect talk about 3D and convergence, then, but first up, Stokdyk’s comments on working with Sam Raimi.

Sam has a great sense of humour, so he is constantly trying to have fun and make the process enjoyable, and to create a creative environment. I can throw out crazy or ridiculous ideas and he may make fun of me for it, but he’ll always listen and I’ll always consider what he says. And that’s what I love about it. We’ve got a level of trust, where he trusts that there’s a reason why I might say something or ask something. It’s a nice environment where you feel like you can contribute creatively, and that’s what I love most about working with Sam.

I can disagree with Sam and he’ll respect my opinion, so I try not to put roadblocks in. But this film is one where we liked to visualise the 3D convergence on set and then when it came time to shooting, go to straight and just re-converge in post-production. This was such a heavy visual-effects shot that it makes a huge difference, and I personally don’t feel like we’re sacrificing anything visual at the end of the day.

If you’re converged with the camera while you’re shooting, you get more key-stoning and warping artifacts between the right and left eye. You either have to do a lot of post-production to take this out, or you live with it, and you deal with the eye-strain that causes.

From the beginning, Ed Marsh, our stereographer, and myself, wanted a really pleasant, comfortable experience. We wanted to push the depth, but we wanted a comfortable experience. And I feel that when you shoot converged, you either have to do so much correction between the edges of the frame in post, that you might as well have shot parallel, or you live with it and it’s not as pleasant for the viewer.

With Sam, as much as there are things that are sticking points where I’m able to exert some influence over him, I can tell when there are some things that are really precious and important to him. He’s a very visual director, but he’s also an actor’s director. It’s critical to Sam to get a really meaningful, interactive performance on set. That includes the performance between our CGI and our actors.

OZ: THE GREAT AND POWERFULSam put me on the spot in a couple of meetings early in pre-production about how we were going to do that. And there’s a long history in visual effects of actors talking to an empty blue screen, or a tennis ball on a stick, and trying to perform, and they have to use their imagination to visualise what’s there, as well as to perform.

So the China Girl is a response to that and if you’re doing, nowadays, a CG character that’s the same size as an actor, it’s common practice to put the actor in on set and paint them out later. But we weren’t able to do that, so with the China Girl, who’s 18 inches tall, and – of course – Joey King is much taller than that, early in production we were looking for a reference for a marionette or doll’s motions might be, and everyone started looking at the performance of Philip Hooper, a master puppeteer. Everyone fell in love with what he could do, and the vision of life he created with an inanimate object.

So Sam brought Hooper in, and he did some tests, and everyone was so impressed with how engaging this character was. You felt the life, just being around this marionette, so we figured that would translate well to set. So our solution was basically to put the marionette on set and then paint it out and put in CG.

For the monkey, we didn’t have an equivalent, and a puppet monkey didn’t quite have the same charm and life as the marionette of China Girl, and in addition it had wings – there wasn’t the same solution for the monkey. So what we decided to do was we would have Zach Braff, even though the monkey was three feet tall and Zach’s over five feet. We tried to put Zach’s head where the monkey’s head was. And when that didn’t work, when the monkey was hovering, or walking along, or hunched over on the yellow brick road, what we tried to do was a second innovative thing, which was not super high-tech but we had a monitor and a camera at the end of a long pole, so we had a puppeteer putting in a proxy for the actor’s head in the space on set where that actor’s head would be. We called that “puppet-cam”.

So we would have Zach Braff in a soundproof booth, which we used for China Girl sometimes too, right off stage. And from the set, James Franco was able to look at this floating monitor, with Zach’s head on the monitor, so they were able to a video conference live on set. And the technology to do that isn’t crazy, bleeding edge technology, but is an interesting use of somewhat ordinary technology. I feel like we were innovative there.

Several artists spent 4-6 months on our clouds and smoke effects. We’ve become much more sophisticated with our fluid dynamics these days, our lighting models are so much more physically accurate now, and we’re basically trying to reproduce the physics of how light scatters in mediums like smoke. We get a very realistic feel based on a lot of intense calculations.

And a lot of hard work. Impressive end results, though. This fakery actually looks tangible.

Thanks again to Scott Stokdyk for taking the time to talk to me.

Oz the Great and Powerful has been available on DVD and Blu-ray in the US for a couple of weeks now, I believe. The UK release is set for July 1st.

(Last Updated June 26, 2013 5:10 am )

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