It makes perfect sense that Jon Farhat was hired to oversee the VFX production of Hansel and Gretel: Witch Hunters. After all, Farhat worked with Timur Bekmambetov on Wanted, and that's pretty much the vibe that that Norwegian director Tommy Wirkola (the Nazi zombie horror/comedy, Dead Snow) wanted for his first English-language movie. Lots of kick-ass action with plenty of dark humor.
Fifteen years after siblings Hansel (Jeremy Renner) and Gretel (Gemma Arterton) outwit the witch in the gingerbread house deep in the forest, they become bounty hunters who exterminate witches. But they find themselves in the middle of a Blood Moon ritual sacrifice of children in a town where they must confront a band of witches led by Famke Janssen and a troll named Edward.
Filming took place in 2011 in Germany at the famed Babelsberg Studio, in a forest near Berlin and in Braunschweig. Half of the movie was shot natively in 3-D (by lead stereographer Florian Maier and his team from Stereotec) and the rest was post-converted by Stereo D. However, 3-D was not part of the original plan but Paramount insisted on it, so Wirkola embraced it wholeheartedly with an in your face approach. Speaking of in your face, there were even two versions tested when the release date got pushed back a year, and the more graphic R-rated version tested higher, to the director's delight.
As for the VFX, it comprised around 800 shots (the plates were shot with the Red Epic), mostly for Troll close-ups, CG enhancements of witches flying on broomsticks, and witch transformations involving Janssen's character, Muriel. These were all done by Hammerhead, the lead VFX company.
"Most of the visual effects were pretty straightforward," Farhat admits. "I think Hammerhead did some really nice character work on Edward; really a lot of the effects were milking the 3-D concept: a lot of comps and environments and CG towns. But, probably, the biggest challenge was trying to do all of that on a very limited schedule and do it in 3-D. And, honestly, schedule more than money dictated the decision not to shoot it all natively. We had Arri Alexas on the splitter rig and it's very large and they had that on a techno-crane. And there were a lot of fight scenes, so it would've been a challenge for the stunt coordinator and second unit director to not do all the camera tricks you normally do. So you've got to get in and out of those sets very quickly and there was a lot of running between trees in the forest, so the native photography was done on sets that you could control."
The biggest issue, according to Farhat, was trying to match flat photography to conversions and have it intercut with native. Typically, with native, you have action coming forward and the picture playing into the seats, whereas with conversion your depth is from the screen backwards; and so in order to blend it seamlessly they had to generate a lot of 3-D elements and fly them in the comp forward in the picture plate. That's why you see a lot of arrows flying forward along with debris and blood and guts and bullets.
While the troll was done mostly animatronically, there was a lot of CG face replacement by Hammerhead to get the expressions right and also when he briefly talked. "But we also had a completely CG Edward when he busts out of the 3-D forest line and runs forward and grabs a tree and leaves and debris," Farhat explains. "He's particularly effective during an over the shoulder scene with Gretel, where they changed his whole face in there.
"But one of the problems is that the character's eight feet tall, so the arm pits of actor Derek Mears were more than a foot below the real arm pits, so the troll could never really raise his arms over his head. And when he needed to lift his arms, we were attaching CG things." Hammerhead did the modeling in Maya and used Nuke for all the compositing.
"The other thing is a lot of exteriors were shot on set so we added a tremendous amount of plates and generated skies so that we had volumetric clouds. There were a lot of pieces and we had witches flying on brooms and the casting was such that except for Zoe Bell, who's a fantastic stunt woman, who played the more aggressive witches, we used a lot of local actors. They struggled to sit on a broom, much less fly and flip around on the thing, so putting them on wires and flying them around set was not doable. So we put them on broom rigs and we just had to fly the set past them, so we shot a lot of cable cam of backgrounds flying through the forest, and since Tommy's style was to put the camera with the witch, it was like looking at the car next to you on the freeway. You're just seeing the backgrounds moving."
As for the witch transition scenes, they turned her into the ugly witch with a combination of CG and makeup. But what's interesting is that the CG Candy House was done late in the schedule by Framestore. There was a Candy House set built, but it proved logistically unsuitable. "By the time we shot, we essentially roto'd the kids out and created an entire CG Candy House with dripping frosting and real volume type of transparent candy, and then, of course, generating that for both the left and right eye. That was pretty aggressive and one of the things when it's all said and done you go, 'That was a nice set they built.'"
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Bill Desowitz is former senior editor of AWN and VFXWorld, the owner of Immersed in Movies (www.billdesowitz.com [1]), a columnist for Thompson on Hollywood at Indiewire and author of James Bond Unmasked (www.jamesbondunmasked.com [2]), which chronicles the 50-year evolution of 007 on screen, featuring interviews with all six actors.
Links:
[1] http://www.billdesowitz.com/
[2] http://www.jamesbondunmasked.com