Vikram Bhatt has always loved experimenting with the visual effects of his films. This time, the producer-director who delivered India's first stereoscopic 3D horror film, Haunted, had a team of 60 people from Prasad EFX working round-the-clock for eight months for his upcoming sci-fi thriller, Mr. X. Starring Emraan Hashmi as Raghuram Rathod, the film is about a scientist who turns into an invisible vigilante - Mr. X. "Over 70 per cent of the film and every scene featuring Emraan makes use of visual effects," reveals K V Sanjit, VFX Supervisor, Prasad EFX.

He explains that the narrative follows a day and night sequence. Rathod can be seen in UV rays and sometimes at night under certain conditions, that Sanjit refuses to reveal.

Sanjit has known the Bhatts since Haunted and insists you can't cheat Vikram. "He knows what he wants and reviews the film, pixel by pixel, nothing misses his eye," he says.

Sanjit informs that Amyra Dastur had to shoot every action scene twice - Once with the hero and once without him. "In the middle of a dialogue, Emraan would disappear so we had to shoot two different tracks. The script was being shot live and we were animating the sequences in parallel," he explains.

Buzz is, the film is inspired by Hollywood films, Hollow Man and The Invisible Man, and Boney Kapoor's Mr. India. But Sanjit insists that the only similarity is the invisible man. "Mr. India has a gadget that brings him back, Mr. X doesn't," he says.

For an underwater, romantic sequence, the cast unit struggled to make the visuals look passionate. "Amyra was without an oxygen mask underwater and had to kiss...nothing at all, since we were animating Emraan's face for the shot. Initially, she looked like she was suffocating instead of romancing," he reminisces.

Then, there was an action sequence in which Emraan jumps from a bike on to another vehicle, and disappears while he's riding. Sanjit points out that they couldn't use a CGI model because they had to capture the shadows, the tilting of the bike and Emraan's body language. "All the VFX had to be incorporated into the action which made the whole process tedious. During editing, we erased Emraan from the frames," he explains.

He adds that every scene had to be tracked individually, then matched with the moves and finally processed for animation, lighting, compositing and rendering. "Since it is a 3D film, the rendering for both the eyes had to be done separately. That meant five days to animate a scene for the right eye and probably two-and-a-half days for the left one," he says. "After that, each shot had to be checked using 3D glasses so that it didn't hurt the eye when played on the big screen."

Despite all the precautions taken during filming, an improper line of sight was noticed during post-production. "We had to use hundreds of layers to match the scenes. We modelled Emraan's body digitally, down to his hair and fingernails, and fixed everything frame-by-frame," he recalls. "We couldn't use a body double because the body language would not match. So we had to manipulate audio, video and facial expressions. Emraan was a complete sport and agreed to even shoot those portions where he wouldn't be seen on screen."