Prime Focus World featurette - "3D Conversion for Gravity"

“I was stunned, absolutely floored. I think it’s the best space photography ever done, I think it’s the best space film ever done, and it’s the movie I’ve been hungry to see for an awful long time.”
James Cameron

The critical reception for Gravity prior to its theatrical release was unprecedented. Following its world premiere at the Venice Film Festival 2013, and screenings at the Telluride Film Festival and the Toronto International Film Festival, anticipation for the movie was at an all-time high, and many of the early reviews were pointing to the ‘outstanding post-production 3D conversion’ (Variety) and the ‘exemplary 3D work’ (The Hollywood Reporter). As the exclusive 3D conversion partner on Gravity, Prime Focus World is delighted to have been a part of the team that delivered this ground-breaking, game-changing movie. 

Prime Focus World’s journey on Gravity began back in 2010, as the London View-D™ team was completing the stereo conversion of The Chronicles of Narnia: The Voyage of the Dawn Treader. Nikki Penny, Executive Producer on Gravity, approached PFW with a proposition – take a single eye from an early native stereo test shoot and convert it, to allow a side-by-side comparison to be made between the native and converted footage. 

The test footage had been shot in a tight set, designed to replicate a space capsule, and the filmmakers had faced issues accommodating the bulky stereo camera rig; so director Alfonso Cuarón and producer David Heyman were delighted when the converted footage that PFW produced was shown to be just as impressive as the natively captured footage. 

“When technological constraints start to hinder the filmmaking, it’s time to look for new solutions,” said Matthew Bristowe, SVP Production, View-D and VFX, Prime Focus World. “We talked the filmmakers through our work, our experience and our stereo expertise, and produced a stereo test that was indistinguishable from the native footage. In the end, it was a pretty easy call to make.”

With the decision made to partner with Prime Focus World to convert all the live-action elements of the movie, the filmmakers were free to shoot the film with mono cameras, allowing Cuarón and his team to stage the action with none of the technical restrictions or compromises of the bulky stereo rig.

So began a six-month pre-production period for Prime Focus World, in which Senior Stereographer Richard Baker worked closely with Cuarón and Gravity Stereo Supervisor Chris Parks to understand the vision for the 3D, and to plan the creative depth choices for the conversion.

“Chris had built a depth plan for Gravity, developed with Alfonso,” said Richard Baker, Senior Stereographer, Prime Focus World. “Chris, as an accomplished native stereographer, brought to the production a very technical, exacting eye for 3D detail – both in the characters and in the depth of the scene. The experience of working with both Chris and Alfonso was fantastic – the vision for the 3D was crystal clear from the start.”

“Many of our early discussions about the stereo concerned the contrast in style between the exterior and interior shots,” continued Richard Baker. “Part of the vision for the stereo was to create a contrast between the vast, unending feeling of space for the shots outside the capsule with the claustrophobia, isolation and loneliness of the interior shots in the close confines of the capsules – something that I feel really comes across when you see the film.” 

An early challenge for Prime Focus World to consider was the integration of the converted live action shots that PFW would be producing and the stereo rendered CG that would be contributed by primary VFX partner Framestore, under the guidance of VFX Supervisor Tim Webber. 

“We have a great working relationship with Framestore, and early meetings with Nikki Penney and Tim Webber allowed us to ascertain what assets were available, what assets we could share, and how we were going to approach certain technical challenges that we anticipated,” said Richard Baker. “Normally on a conversion we would take delivery of locked final shots. On Gravity, the assets were ‘live’ – work-in-progress - and we were dealing with various types of shot: full drama conversion shots; conversion of mono plates to be passed back to Framestore with newly created stereo cameras to add stereo CG elements; and shots provided by Framestore as final 2D VFX shots to be converted.”

It fell to the PFW pipeline team, working closely with their counterparts at Framestore, to anticipate and pre-emptively solve the issues raised by this new way of working. 

“Due to the nature of the show, and the immense complexity of the sequences, we knew that we were going to be working on live shots, and that there was going to be a lot of passing back and forth of work-in-progress shots between ourselves and Framestore,” explained Rajat Roy, Global Technical Supervisor, Prime Focus World. “One of the biggest initial issues we identified was that Framestore were rendering stereo CG elements to be dropped into our converted plates – floating pens, straps, helmets etc., to sell the effect of weightlessness inside the capsule – but the VFX was not locked when we were converting the shots.” 

“In order to ensure that the stereo rendered CG elements matched the conversion exactly, in terms of their volumetric properties, we created highly accurate stereo cameras that we then passed back to Framestore – allowing them to render their stereo CG elements using our cameras,” continued Raj. “To create a stereo rig that was accurate for both our conversion and for Framestore’s stereo renders required a huge amount of mathematical effort – entirely new mathematical modeling that was unique to this show.”

The ‘work-in-progress’ nature of the shots had other technical implications for the PFW pipeline team – both in terms of asset tracking and maintaining flexibility in the unfinished shots. 

“We realized immediately that asset tracking was going to be complicated – and of course hugely important – on this show,” commented Eoin Greenham, Global Head of View-D Pipeline, Prime Focus World. “Prime Focus World and Framestore were sharing a wealth of information on this show, and both companies use proprietary formats and tools, and various third-party software and plug-ins. It was important that our pipe tools understood their assets, and vice versa. But also, due to the live nature of the work, any amends to a shot by Framestore had to be reflected in the assets we were using in the conversion, to ensure that our passback was built using the latest versions. Production management was a considerable task, involving four times the amount of data than we have had on other shows, but we solved this early through a close and open collaboration with Framestore.”

A second technical implication of the work remaining live through the conversion process was maintaining flexibility in the assets. 

“Alfonso is a visionary director, who builds his narrative by keeping his options open as late as possible, to ensure that he is using the best shots to support the emotional arc of the film,” continued Rajat Roy. “This makes things difficult – especially in a dual-pipeline like the one we were building – because shots don’t get finalized until a late stage in the process. As a result, we have to keep all our work in a flexible manner, so that shots can be changed, amended or reverted as the cut comes together – and this means keeping a lot of assets live.”

The storage implications of keeping all the assets and versions live were compounded by another element of Alfonso’s directorial style – the length of the takes.

“Everyone with an interest in filmmaking is familiar with the long seamless shots that Alfonso and cinematographer Emmanuel Lubezki created for Children of Men,” said Matthew Bristowe. “On Gravity, Alfonso and Emmanuel have gone one step further. The long, unbroken, floating camera shots work spectacularly well in space, and led to us producing the longest continuous shot that I believe has ever been converted – 15,531 frames, or 10mins 47 secs.”

“That length of shot is a huge challenge in any VFX process,” continued Richard Baker. “When you factor in the number of long shots we had to deal with, and the sheer number of assets that we use in conversion, it is pushed to another level. The size of the Maya files, the Nuke and Fusion scripts, the amount of roto, the amount of clean-plating required to remove the characters from the environment – for shots up to 11 minutes in length - these factors all add up to huge file sizes, unprecedented render times and new processes for both the completion and review of the shots.”

In order to handle the longer shots, the Prime Focus World technical team not only augmented the pipeline with pre-comp techniques to make the work more manageable, but also broke these shots into shorter sections to parallelize the efforts of the artists, with a keen eye on the ‘joins’ where the artists’ work met, to ensure consistency of depth and sculpting across the scenes.

“This was a new form of collaboration for our artists,” said Richard Baker. “It was essential that the out and in points of the sequences within the long shots matched seamlessly, in terms of sculpting and depth, and our leads painstaking ensured that the joins locked with no jarring moments for the viewer – even subconsciously.”

With technical solutions for some of the initial issues in hand, Senior Stereographer Richard Baker was able to focus fully on the creative aspects of the conversion. Following detailed conversations with Alfonso and Chris Parks, Richard and his team began putting together ‘design frames’ (d-frames) to start defining the stereo look of the conversion.

Using LIDAR scans of the capsule sets, and cyber-scans of lead actress Sandra Bullock’s head, Richard modeled these early frames to exactly match the scene as if the stereo had been captured natively, with a view to producing a ‘technically exact’ stereo image as a starting point for the conversion. But even this was not without its technical complications.

“We used LIDAR scans of the capsule sets, and cyber-scans of lead actress Sandra Bullock’s head to produce depth mattes,” recalls Eoin Greenham. “However, because the crew was dismantling and reassembling the set around the camera rig as it moved through the tight confines of the capsule set in its long takes, the LIDAR was not completely accurate. We had to rebuild the environment with augmented tracking in order to produce the depth mattes, which we could then use to ensure the accuracy of the conversion, and a consistency of depth across all our shots.”

From this starting point, the stereo in the characters and the environment could be manipulated by Richard and his team to produce a more ‘pleasing’ stereo image.

“Chris [Parks]’s background is in native stereoscopy, and the flexibility in conversion to manipulate the stereo image was definitely something he appreciated,” said Richard Baker. “As we worked together on the look of the stereo, I was able to present Chris with creative options, and through the control we have with View-D, we were able to achieve exactly the stereo look he envisioned.”

“The single biggest disadvantage of native shooting is that you have to lock your stereo on-set,” opined Rajat Roy. “This is a very unnatural thing to do, because the set is a very unnatural place. You wouldn’t lock your sound on-set, trying to capture a live mix. Just as you wouldn’t lock you grade on-set, trying to set the look of the film with gels on the lights. There is so much extra added value from a good Foley track and sound mix, and from a good colour grade – these are extra filmmaking devices that are at their best when crafted by experts. Exactly the same is true of stereo. Once the edit is assembled, and you know what you want from the stereo, you can craft it to support your storytelling.”

“When shooting natively, you are essentially working with a single stereo camera set-up,” added Richard Baker. “In conversion you can have multi-camera set-ups, and each of these cameras can relate to a different part of the scene. Animation companies such as Pixar and Dreamworks work in a very similar way when producing their stereo movies. This gives us full control over the amount of depth in foreground, midground and background objects, allowing the stereo to be crafted to support the creative demands of the scene.” 

“Some of the depth choices we made would have been very challenging, if not impossible, to capture natively,” continued Richard Baker. “Whether it was physically getting a bulky stereo rig inside the capsule set, or achieving the level of control over the stereo that Alfonso demanded, it was clear that native was not the way to go. In the conversion we had the flexibility to manipulate the imagery, focusing attention on the characters in ways that would have been hugely difficult to achieve with a stereo camera, thereby enhancing the emotion in the scenes. We could use the depth to enhance the feeling of claustrophobia; to promote a feeling of isolation; to create a wildly agoraphobic feeling of being an insignificant speck in a huge void. We used all of these stereo techniques, and more, on Gravity.”

“There is often little or no dialogue in the capsule scenes in Gravity,” offered Matt Bristowe. “Our job with the conversion was to help captivate the audience with the beauty of the 3D visuals; to support and enhance the emotion of the scenes using all the stereo techniques in our arsenal; and to help forge an intimate connection between our lead character and the audience, that ensures that they are with her every step of the way in her intense struggle to survive this terrible situation.”

Gravity was a project that pushed Prime Focus World’s View-D™ conversion and pipeline teams to the limits of what was possible – just as it was pushing every other aspect of film production; from the visual effects, to physical on-set practical filming techniques, to the actors themselves.

“Gravity demanded the very best from everyone involved. The director was totally uncompromising, in the best possible way,” said Eoin Greenham. “It was a huge creative challenge – and an equally huge technical challenge. Many of the things we put in place for Gravity had never been done before, and we were dealing with unchartered territory and technical unknowns – with pressing deadlines and a challenging director. Solutions had to be created at a moments notice, because we were part of a chain – and if a single link in that chain had broken, it would have brought a whole series of dependencies crashing down.”

“We knew the challenges we were taking on,” agreed Rajat Roy. “We knew that this show would be different and difficult – and that is exactly what we want. We made ourselves the only conversion company in the world capable of delivering this show: creating a new pipeline that integrated with an external VFX pipeline; building new algorithms; devising new proprietary tools; developing new software; and incorporating third party software. We now have a mature pipeline for keeping assets open and live with VFX companies, taking VFX assets and making them non-proprietary, allowing the conversion to start much earlier in the filmmaking process, and ultimately giving us more time to craft the stereo.”

“Prime Focus World delivered 85 final shots for Gravity – which may not sound like a lot, but when you consider the length of some of the shots, we’re talking almost 30 minutes, or one third, of the show,” concluded Matthew Bristowe. “But this project wasn’t about the time, or the money. Gravity is unlike anything you have seen before. In terms of 3D, this film is a game-changer. In terms of filmmaking, it’s a quantum leap forward. It’s one of those movies that we’ll all look back on later in our careers and be extremely proud to have worked on.”

“There was a time, perhaps, when conversion was seen by some as an afterthought, tacked onto the end of the filmmaking process to sell more tickets,” added Richard Baker. “Gravity is here to bury that thought once and for all. Prime Focus World was an integral part of the creative filmmaking process on Gravity, delivering an extra level of emotion; an extra level of drama; an extra level of immersion; and an extra level of filmmaking control for the director. I’m delighted that Alfonso Cuarón chose Prime Focus World to deliver his 3D vision.”

RELEASE: October 8, 2013 (US)

Academy Awards - 7 Awards including Best Director and Best Visual Effects
BAFTA Awards - 6 Awards including Best Director, Best Visual Effects and Best British Film
Visual Effects Society Awards - 6 Awards including Outstanding VFX in a VFX-driven Movie
International 3D Society Creative Arts Awards - 4 Awards including Best 2D to 3D Conversion and Best Live Action 3D Feature Film
Directors Guild Awards - Best Director for Alfonso Cuarón
Producers Guild Awards 2014 - Best Film (tied with '12 Years A Slave')
Critics Choice Movie Awards - 7 Awards including Best Director, Best Cinematography and Best VFX
VES 'Visionary' Award for Alfonso Cuarón
Golden Globe Award - Best Director for Alfonso Cuarón
Golden Tomato Award - Best Reviewed Film of 2013
LA Film Critics Award - Best Film (joint winner) 


Director: Alfonso Cuarón
Producers: Alfonso Cuarón, David Heyman
Studio / Distributor: Warner Bros. Pictures

PFW Supervisor: Richard Baker
PFW Producer: Matt Bristowe
PFW Scope of Work: 3D Conversion
Exclusive Conversion Partner
PFW Lead Facility: London
PFW Associate Team(s): Mumbai


 PFW Gravity Brochure

PFW Gravity Brochure

I think the 3D is a character in the film, in a way, or it contributes to the character.

- David Heyman, Producer, Gravity

The important thing of the 3D is the immersive aspect of it. It’s almost as if you are going to a virtual reality show, and you are sent into space, into this very scary adventure.

- Alfonso Cuarón, Director, Writer, Producer, Gravity

With the 3D, you’re going to be feeling like you’re abandoned in space, floating untethered.  It would be really hard for somebody to watch this and not feel like they are there.

- Nikki Penny, Executive Producer, Gravity