By IAN FAILES
In Aanand L. Rai’s Indian Hindi-language Zero, a romantic comedy released in the U.S late last year, one of the central characters is a man described as ‘vertically challenged.’ However, the 4-foot 6-inch character, Bauua Singh, was played throughout the movie by Indian star Shah Rukh Khan, who is 5 feet 10 inches tall.
That meant his smaller stature needed to be created with the aid of visual effects, a feat achieved by Mumbai-based Redchillies.vfx. VFX Voice explores with the studio how the actor was transformed for extended periods in the film.
One of the main challenges Redchillies.vfx faced was ensuring the eye line between actors in the scene would be convincing, even during fighting or dancing sequences. “We were quite clear that we didn’t want to shoot the protagonist separately and then composite him in the scene later, as this would be possible only for one or two minutes duration and not for the entire film,” outlined Redchillies.vfx Chief Creative Officer and Visual Effects Supervisor Haresh Hingorani and Chief Operating officer and Visual Effects Producer Keitan Yadav, in a joint response. “That’s when we realized we had to shoot all of them together in the same scene.”
The process began with a photogrammetry scan of the actor, with the resulting 3D scan of his body shrunk down to provide a visualization of how he would look as a smaller person. “The previsualization team planned the scenes which were then executed on the set,” notes Hingorani and Yadav. “We had a 4-foot 6-inch stand-in whom we used as a reference. We scanned him for on-set composition and camera placement. This helped us gauge the height ratio that needed to be shrunk.”
For the eye lines, in particular, Redchillies.vfx initially considered attaching a patch of light to the actor’s chest so that others could look there, while the actor himself looked upwards. But, says Hingorani and Yadav, “this method got awkward as there were a lot of emotional, comedy and interactive scenes which would feel weird acting out looking at the actor’s chest.”
Instead, the sets were built to accommodate the height differences. They stood one-and-a-half feet above the true floor, thanks to block pieces. When Khan needed to walk through a scene, the necessary blocks were removed and he effectively walked through a lower pit. For outdoor locations where creating a pit wasn’t possible, ‘anti-pits’ were created. “Here,” explains Hingorani and Yadav, “the co-stars would stand on top of the boxes and perform while Khan would stand on the real surface. In both these scenarios, we re-created the fake floor in CG throughout the movie.”
The actor’s legs were occasionally re-created in CG, too. For these shots and others that involved the pits, the camera move was acquired with a motion-control TechnoDolly. The DOP acquired five plates. The first was for previs, the second was a plate of Khan inside the pits, the third had the actor and co-stars acting at the same ground-level, the fourth had the co-stars repeating their actions but without Khan in the frame, and finally the fifth plate had the actor use ‘larger’ gestures, since his body would be shrunk down later. An additional pass for HDRI photography using a chrome ball was used for reference lighting.
In general, compositing techniques such as spline grid warping were used to shrink down Khan, using his and the body double’s 3D scans for reference. Sometimes, manipulating the main character digitally was not the only way that the height changes and differences were achieved. Optical illusion techniques also became part of the mix, as Hingorani and Yadav outline.
Initially we did consider creating bigger sets and using forced perspective, but since the entire film had interactions between actors, this kind of forced perspective wouldn’t have worked. We used slight forced perspectives in solo scenes of the actor. Like when he’s sleeping, we would use a bigger bedsheet or bigger pillows. A lot of the other props were also shrunk as and when required, but this was a very small portion of the entire 130 minutes.”
One of the most complicated scenes in the movie revolved around the song “Mera Naam Tu,” in which the director wanted to reflect the vibrant colors of the Indian festival of Holi. The song also plays out with a slow-motion feel (the scene was shot at 48 fps) and elements such as water droplets of bursts of colored powder are highly visible (they were computer-generated).
Redchillies.vfx re-created the entire set for the song sequence in CG by Lidar-scanning the area. The colored powder was realized as an effects simulation in Houdini with more than 25 variations of chunk and mist layers. Raindrops were, similarly, effects sims made up of more than 50 variations. Both colored powder and water droplets had to interact with the actors, which required extensive matchmoving and tracking.
“In the song,” describes Hingorani and Yadav, “we can see Khan dancing with a group of kids. Timing was crucial here as it required coordination between the protagonist and the kids dancing, as well as the colored powder interactions with the leg movements and with the other characters to create a magical effect. Leg interactions with the colored powder were simulated with the help of matchmation of the children and rendering with the projection cut-matte of children and the actor. Each dancer’s legs interaction with the floor contained more than 15 CG layers.”