Facts less known : A technical view of James Cameron’s AVATAR

Be a gadget, movie, machine, building or any man-made marvels, I would like to have a knowledge on what technical work has gone in the background. This post is out of one such venture by me online/offline for Avatar. The Sci-fi block buster directed by James Cameron and produced by 20th Century Fox, Avatar is yet another CG (Computer Graphics) marvel and the highest gross feature film ever made. More than 80% of the film is virtual consisting 110 minutes of full CG and 20 minutes of live action - CG combo.

VFX companies

The lead visual effects company that brought Jim’s vision real on screen was Weta Digital in Wellington, New Zealand. It has won two academy awards for visual effects in The Lord of the Rings and King Kong along with an Oscar nomination for I-Robot.

Though the major elements like the Pandora environment, characters and creatures were developed at Weta, to help finish the special effects sequences on time, a number of other companies were brought on board, including Light & Magic, which worked alongside Weta Digital to create the battle sequences. ILM was responsible for the visual effects for many of the film's specialized vehicles and devised CGI explosions. Others were BUF, Halon, Hybride, Hydralux, Lola, Pixel Liberation Front, Stan Winston studio and the Third Floor.

Tools

Hundreds of animators, computing specialists working with a plethora of technologies and experimenting new techniques, brought out Avatar for Jim.

AutoDesk’s Maya and Motionbuilder were two major tools used, where the former created 3D stereo graphics and the later helped in real time motion capture integration and rendering.

Adobe Photoshop was used to create many of the ultra-high resolution matte paintings and textures that were used as finished artwork passed along to the 3D pipeline for CG environments, vehicles and creatures.

AdobeLight room was used by artists in the previsualization stage to organize and catalog the thousands of set and lighting reference images.

Adobe After Effects was used to automate rough compiling of the video of the facial performances of the actors into CG character. It was also used to create complex motion graphics for use in the 3D holographic screens in the various control room scenes, and to create “heads-up” displays for various high-tech vehicles in the film.

Adobe Premiere Pro was used for creative editing and immediate review

Acrobat Connect was used for collaboration throughout the making of the film like sharing data with the crew for review and changes after immediate rendering.

Shooting Techniques:

Performance capture: The process of recording movement and translating that movement onto a digital model. It is used in military, entertainment, sports, and medical applications. In filmmaking it refers to recording actions of human actors, and using that information to animate digital character models in 2D or 3D computer animation. When it includes face, fingers and captures subtle expressions, it is often referred to as performance capture.

Nearly 120 industrial cameras from Basler vision were rigged up around the set. The floor was marked with a grid, marking the areas covered by each camera. The actors wore special black leotards, with white reflective spots stuck all over. The cameras tracked the movement of those dots, not of the actors.

Computers receiving that camera feed would create rough virtual characters, moving in exactly the same way, instantly. When Zoe Saldana, the lead actress moved, a crude model of Neytiri, her virtual avatar in the computer, mimicked her actions. This was not new for Weta as they have already mo-capped for King Kong and LOR

Real time facial Expression: This was completely a new venture by Weta demanded by Jim. We quickly lose interest in digital faces that don't properly emote. To make his avatars believable, Cameron made real human actors act out everything. While wearing special headgear, with powerful inbuilt cameras.

Avatars had eyebrows which would show most emotions clear-cut, but Navi’s din’t have. To compensate that every movement of the eyeball, dilation of the pupil, quiver of the lips, tightening of muscles under the skin was recorded and fed to a computer. The processing system has to deal with a world that is interactive and unpredictable. It is not possible to know where the actor is going to be in the next few seconds; therefore, it is not possible to plan the shots as a film maker would do. To solve this issue, the system relies on artificial intelligence to select the most appropriate shots which was used to create expressions for the digital characters.

3D Cameras: Real humans often share screen space with the visually rich digital characters in Avatar. To ensure they didn't look out of place, they had to be shot in three dimensions.

Till recently, 3D cameras were the size of a fridge. And weighed 250 kilos. Two separate cameras, kept a few feet apart, and moved together by huge cranes would record shots, which would later be played by two separate projectors at the theatre.

Cameron made a light, twenty five kilo 3D camera, Just like our eyes, it's got two separate inbuilt lenses, which move and change focus on objects independently. A computer combines the images they record and overlaps them to create a 3D effect.

Virtual Camera: This one's a simple notebook sized LCD screen, with video game like controls built in. But it displays the virtual world being generated by supercomputers, not the real set he's actually shooting in..

Directors who used computer graphics earlier would have to imagine what their final shots would look like. With the virtual camera, Cameron had it all right in front of his eyes. He could walk to different corners of the set, or change his height from the top of a tree stump to onboard a hovering helicopter. Weta’s supercomputers would sense where he was on the grid and recreate his virtual planet from that perspective. He could choose a final shot from wherever he pleased on the grid, and the computers would faithfully generate it.

The Data Center

To render Avatar according to Paul Gunn, Systems Administrator at Weta , they have used a 10,000-sq foot server farm with 4,000 HP blade servers with over 35,000 64-bit processors in their data center with all of the rendering nodes using Red Hat enterprise Linux and 90% of their desktops running Ubuntu. Weta Digital has one of the world’s largest Linux clusters. It is ranked #193 amongst the top 500 supercomputers of the world with processing capabilities of 10 Gigaflops.

Creating the Na'vi characters and the virtual world of Pandora required over a petabyte of digital storage. For the last month of production the systems were handling 7 or 8 gigabytes of data per second, running 24 hours a day. A final copy of Avatar equated to 17.28 gigabytes per minute of storage.

Note : The information, statistics and images were purely attained out of interest by Googling and from the magazine Computer Graphics world . This post contains information from various web sources like forums, wikis etc. Links are below.

Links:

Making of Avatar at Youtube

http://www.youtube.com/watch?v=7c4kNLz_4E8

Computer Graphics World - CG In Another World

http://www.cgw.com/Publications/CGW/2009/Volume-32-Issue-12-Dec-2009-/CG-In-Another-World.aspx

Wiki highest gross films

http://en.wikipedia.org/wiki/List_of_highest-grossing_films

Avatar and Weta Digital

http://en.wikipedia.org/wiki/Avatar_%282009_film%29

Linux and Avatar

^{http://www.linux-netbook.com/10-blockbusters-made-with-the-help-of-linux}

Weta Data center

http://www.datacenterknowledge.com/archives/2009/12/22/the-data-crunching-powerhouse-behind-avatar/

Jaimon Joseph’s Blog

http://ibnlive.in.com/blogs/jaimonjoseph/326/54022/cutting-edge-tech-and-the-making-of-avatar.html

^{Adobe products in Avatar}

^{http://www.webkitchen.be/2009/11/26/a-peek-behind-the-scenes-of-avatar/}

Motion Capture

http://en.wikipedia.org/wiki/Performance_capture

Virtual camera system

http://en.wikipedia.org/wiki/Virtual_camera_system