Gravity’s iconic opening scene: all you need to know

In space, no-one can hear you ask... how did they do that?!

Alfonso Cuaron only had one condition when he pitched ‘Gravity’ (out on Blu-ray 3D, Blu-ray, DVD, on March 3 and digital download March 2) to the film’s visual effects supervisor, Tim Webber.

“In the first conversation, we talked about photorealism,” Cuaron explained to Yahoo in our exclusive interview above, “[‘Gravity’] had to look like a space documentary. I said, I want us to be sued by NASA when they see the film.”

[Alfonso Cuaron: I believe in celebration, not competition]

Nearly five years later, the film debuted dazzling audiences and industry professionals alike, but there’s still no sign of a lawsuit from America’s space agency.

However, one unwitting South American journalist fell for Alfonso and Tim’s cinematic illusion hook, line, and sinker, quizzing the Mexican director about the technical difficulties he faced shooting in space during a Q&A late last year.

Cuaron, to his credit, scratched his head, cracked a grin, and responded."Yes, we took cameras to the [spacecraft]," he said. "We were in space for three and a half months. I got really dizzy while rehearsing.”

He is, of course, joking. The human parts of 'Gravity’ were filmed strictly on terra firm here in the UK, while the cosmic elements were hand-crafted by Tim Webber and Soho-based VFX firm Framestore.

But how did the film-makers achieve the level of photo-realism that would fool a journalist and earn them dozens of Best Visual Effect awards – not to mention Best Picture nods too - in the process?

[Honest posters for the Oscars 2014 nominees]

It starts with good writing explains Alfonso, who co-wrote the script with his son Jonas Cuaron.

“There was a very precise screenplay. It was a screenplay that suggests and narrates every single beat that you see on the screen,” Cuaron told us, “The screenplay was very rich in descriptions.”

You can read the full screenplay for 'Gravity' here thanks to Warner Bros.

From there, Tim and his team built the film from scratch using basic wire-frame computer modeling and animation, a process known in the trade as “pre-viz”, which usually just helps a director to conceptualise the final product, but in the case of ‘Gravity’, it became the template for the film.

The actors, hooked up to motion-controlled rigs, were placed into the Lightbox, a Framestore creation named one of the 25 Best Inventions of 2013 by Time Magazine.

The Lightbox is a 20ft by 10ft structure, covered with 196 panels of 4096 LED bulbs, used to simulate the unique lighting patterns created by the Earth in zero gravity, but the idea for the ground-breaking construction came from a gig by a veteran rock star.

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“It was Chivo's [Emmanuel Lubezki, cinematographer on ‘Gravity’] idea actually. He was at a Peter Gabriel concert and he saw these panels of LED lights and that’s when he came with the idea,” Cuaron reveals, “The problem is, he came with the idea, but now it was about how we can ground it, and co-ordinate it with the camera moves.” Which is where Webber’s robots come in.

It’s an incredibly innovative approach to film-making which took nearly five years for the Mexican director to take from script to screen – so, were there any regrets now the film was out?

“I wish we’d done it in a way that had taken a year and a half, two years, instead of four and half. [To Tim] Do you think you will be able to do it?” jokes Cuaron.

“Could we do it quicker next time? Yeah… but not much quicker!”

‘Gravity’ is out on  Blu-ray 3D, Blu-ray, DVD, on March 3 and digital download March 2, 2014.

Get a closer look at the tech behind the magic in this 'Gravity' gallery...