The visual effects firms transforming the film industry By Al Moloney

Technology reporter, BBC Click Published duration 23 February 2014

BBC Click takes a look behind the scenes at three of the latest visual effects technologies being used in films.

media caption Creating Gravity's special effects was a long and painstaking process

If you are looking for a sure thing at this year's Oscars look no further than Gravity to win the best visual effects category. Despite containing the combined star power of Sandra Bullock and George Clooney, the real standout of the film has been the work of London-based visual effects company Framestore.

Under the guidance of VFX supervisor Tim Webber, the company worked closely with director Alfonso Cuaron to bring the tale of two stranded astronauts to the screen. Originally conceived as a small, intimate film with practical effects, Webber believed that the difficulty of representing gravity in space, or the relative lack of it, could best be overcome through digital technology.

The end result is a film that is about 80% composed of digital shots. Each frame took around 50 hours to render fully and if the entire film had been rendered using a single CPU processor then it would have taken about 7,000 years.

media caption Actor Kezia Burrows explains how facial expressions can be captured

As performance capture has advanced over the past decade so has the quest to make a realistic human CGI face. Rather than doing away with the actor, the process actually works in conjunction with their performance, tracing and capturing the movements of their face. This information is then fed back into the software to give as realistic a digital performance as possible.

One of the most recent products in this field is the Vicon Cara. Its makers claim that the system is the world's first, out-of-the-box, 3D facial motion capture system. The light-weight helmet is made up of four HD cameras which record their movement and which allow the performer to act without their view being obscured.

While the tech still has some way to go before it can create a truly believable human CGI performance, it has reached a stage where human performances can be altered by visual effects artists afterwards, albeit in subtle fashion.

Phil Elderfield of Vicon points out that: "You can start with the true performance of the day but you can also tweak it a little bit if you want to - you can embellish it or you can play it down, you can emphasis or de-emphasis certain things and by re-creating a [filmed] world inside a computer that flexibility exists."

media caption Spencer Kelly finds out how Bepe the blue alien is created

In 2001 the film Final Fantasy: The Spirits Within was released. The movie may be unfamiliar to many these days but it marked the first widespread release of a film made entirely using motion capture technology.

The studios of AudioMotion are based just outside of Oxford and, while the name may not be immediately familiar, they have worked on some of the biggest films and computer games of the last few years.

The company specialise in motion or performance capture which involves actors wearing a special mo-cap or performance capture suit that is covered in highly reflective dots. The location of the dots is captured by cameras all around a set and visual effects engineers are able to digitally recreate the exact movements of the actor.

The process achieved widespread prominence with the release of the second Lord of the Rings film, The Two Towers, where the performance of actor Andy Serkis as Gollum earned critical acclaim.

The last decade has seen the technology develop further still with more detailed and complex movements able to be mapped while more realistic and human-like creations are now commonplace in films and computer games.