/> Rakeysh OmPrakash Mehra's Delhi-6 might have failed to woo the audience at the box office, but if one were to talk about the visual effects (vfx) work in the movie - done by the couple of Indian studios - the effort is really commendable.

Various vfx techniques, right from compositing, matte painting, background plates (BG), wire removal and many more, went in creating shots which portrayed the look and feel of real Delhi, though most of the sequences were not actually shot in Delhi for security reasons.

For a behind-the-scenes vfx case study of the movie, we spoke to Chennai-based post production house Prasad EFX, which has worked on close to 425 shots for the movie. With around 50 artists, it took 3.5 months to complete all the shots.

Kilari Hima Kumar, Executive Producer-VFX, Prasad EFX says, "It was a great and wonderful experience working with the director Rakeysh OmPrakash Mehra and the team under the supervision of Craig Mumma - the vfx supervisor for the movie."

Apart from Prasad EFX, Mumbai-based Prana Studios also worked on few shots. Here is the breakdown of a few key shots worked on by Prasad EFX:

Terrace Extension:
The terrace shots of Delhi 6 were shot on set in Jaipur but were given the feel of Delhi in post production. Original backgrounds were replaced by images shot in Delhi. The key challenge in this shot was extending the generic terraces, building the geographic landmarks of the area like Jama Masjid, Golden Temple, Red Fort, with their respective geographical positions.

"Craig Mumma had suggested and guided the creation of a 360 degree Delhi geo-environment in 3D with using Delhi terrace photographs. Then we tracked the shots and placed the geos in the respective positions. We had executed about 164 terrace extension shots in this film, " says Himakumar.

Birth sequence:
The entire sequence was shot in green matte and was later composited with another sequence which was shot separately. "Our challenge involved 3D tracking of shots and matching static BG plates. We had stitched the BG's in 3D, composited the environment and matched to the shots. (No of shots - 15)

Brooklyn bridge car sequence:
The Brooklyn bridge sequences were shot in green matte at the sets and were later composited with the BG plates, shot separately. (No of shots: 18)

Taj Mahal interior sequence:
The Taj Mahal sequence was actually shot in green matte because of problem with permissions. Later using the reference of old building and images, a separate new background and location was created in computer graphics (CG) and composited with chroma background. The light coming from the window and falling over Sonam Kapoor, was created in 3D. (No of shots: 11)

Heaven sequence:
After shooting Amitabh and Abhishek on a chroma background, the heaven was designed on the basis of the real Delhi terrace with heavenly white look. The background was made through matte painting and the environment was computer generated. (No of shots :15)

Market and Car Sequence:
In the market sequence, Abhishek along with the other co-stars, were shot against the chroma background and later replaced with market BG plate.

Using the chroma technique, Abhishek and other stars were shot against chroma background and seats which were later replaced by footage taken in a congested area of Delhi with empty car seats.