Maps to the Stars – VFX Q&A

by Graham Edwards

"Maps to the Stars" - visual effects by Switch VFX

Veteran filmmaker David Cronenberg has a reputation for tackling the kind of subject matter that make audiences squirm. His early feature work – which includes Scanners, Videodrome, and The Fly – exposed mainstream audiences to the shock effects of “body horror”, while at the same time getting under their skins with unsettling psychological subtexts.

While Cronenberg’s most recent feature, Maps to the Stars, explores similar themes to some of his earlier films, it dials down the grossness in favour of the psychological. Set against – and satirising – a Hollywood that’s simultaneously larger-than-life and desperately shallow, it explores the intertwined stories of scarred pyromaniac Agatha Weiss (Mia Wasikowska), fading movie star Havana Sagrand (Julianne Moore), TV psychologist Dr. Stafford Weiss (John Cusack), his control-freak wife Cristina (Olivia Williams) and struggling actor Jerome Fontana (Robert Pattinson).

Visual effects for Maps to the Stars were provided by sole vendor Switch VFX, with the exception of a small number of minor shots undertaken by Deluxe. Under the supervision of its co-founder Jon Campfens, Switch delivered around 145 shots, including matte paintings, set extensions and greenscreen composites.

There was a little body horror, too – well, this was a Cronenberg film, after all. In addition to the “invisible” environment work, Switch also developed complex fire simulation effects for a key sequence in which Cristina Weiss sets light to herself beside a swimming pool, and enhanced other scenes involving blood and gore.

In this Q&A for Cinefex, Jon Campfens discusses the challenges involved in turning Toronto locations into the Hollywood Hills, and reveals just what David Cronenberg is looking for when it comes to setting a woman on fire.

Julianne Moore and Mia Wasikowska star in David Cronenberg’s “Maps to the Stars”

Julianne Moore and Mia Wasikowska star in David Cronenberg’s “Maps to the Stars”

How did you get involved with Maps to the Stars?

The line producer, who I know quite well, introduced me to David Cronenberg. We were brought on board a bit late in the project, during prep, as the original VFX company had decided to pass on it. They had already gone far enough down the road on some of the VFX approaches that they could not be changed – especially concerning the fire sequence – so we were locked into doing it that way. We had a number of discussions with David and the creative team to ensure we were all on the same page before we went to camera.

Tell us more about the fire sequence.

During the sequence, Dr. Stafford Weiss discovers that his wife, Christina, has set herself on fire. He proceeds to push her into their swimming pool with a deck-chair to try and save her. Beau Parsons, one of our on-set supervisors, attended the shoot along with Brandon Rogers, a member of our CG team and lead for the department that would be using Fume FX.

What direction did you receive from David Cronenberg regarding the action by the pool?

It was expressed to us by David during the prep stages that the performance comes before anything else. Despite our suggestions that shooting fire elements or using a stunt double would provide more realistic fire, David wanted to go the CG route in order to preserve Olivia’s performance. I am not a great lover of CG fire, but it was the only way to proceed in order to get what David wanted. It was important to him that the audience knew it was really her and not a stunt double using fire retarder – which has a very reflective quality to it.

For the immolation sequence, actress Olivia Wilde was photographed on location, in costume and wearing minimal tracking markers.

For the immolation sequence, actress Olivia Wilde was photographed on location, in costume and wearing minimal tracking markers.

Artists at Switch VFX, under the supervision of Jon Campfens, added CG fire effects simulated using Fume FX, and motion-tracked to Wilde's performance using PFTrack.

Artists at Switch VFX, under the supervision of Jon Campfens, added CG fire effects simulated using Fume FX, and motion-tracked to Wilde’s performance using PFTrack.

Given those parameters, how did you go about executing the fire?

Face replacement was out of the question, because she is moving around quite a bit – as you would be if you were trying to put out a fire. We knew motion capture would be key, to get the fire to interact with her body in a believable way; we also knew we would need to use a fairly minimal rig. We ended up using two DSLR witness cameras synched to the shooting camera to triangulate Olivia’s position. These provided motion capture data through PFTrack – not the most elegant way of doing it, but it’s fast, unobtrusive and cheap.

During the scene, the gown worn by the character Christina burns away to reveal her burned flesh beneath. How did you achieve the transition?

We shot the scene twice, once with Olivia in her gown and once wearing a burn suit. The burn suit was actually very problematic. It took much of the night to prepare, and the tracking markers didn’t want to stay on. By the time it was ready, the sun was starting to come up and we only had time for one run-through. In any case, as soon as she fell in the pool the suit became unusable, so it was very important to get it right on the first try.

How did you integrate the CG fire with Olivia Williams’ performance?

The key to getting the CG fire to react realistically to Olivia’s flailing body was to get a good, useable track. For this we used PFTrack and its motion capture capabilities. Using a three-camera setup, we were able to generate data that allowed us to track her movements in 3D space.

For shots later in the sequence, CG fire and smoke were combined with live-action plates of Wilde wearing a burn suit.

For shots later in the sequence, CG fire and smoke were combined with live-action plates of Wilde wearing a burn suit.

Using a rigged 3D model of Olivia, we attached specific joints to the corresponding locator data returned by PFTrack’s motion capture output. The model was then hand-animated to compensate for the joints that did not return valid tracking data. Once a camera track was achieved, and the witness cameras were lined up properly, we then did an object track for every tracking marker.

What was your approach to the fire and smoke simulation?

We used Fume FX, but we couldn’t get much information on, or examples of, using it with Maya – and we’re a Maya-based company. So we did a lot of R&D, working through all the kinks, errors, and complications.

We generated smoke and fire from the tracked geometry, and rendered countless simulations in order to get what David was looking for. To make adjustments and revisions less time-consuming, we broke down the simulations and renders into smoke and fire passes for individual body parts – arms, legs, torso, etc. This also allowed for more time-friendly simulations at a smaller voxel spacing, creating extra detail in the fire tendrils and smoke. Animated texture maps were created in Nuke, and piped into Fume’s emitter channels. This permitted the fire to start at her legs and spread upwards, completely engulfing her.

Was it difficult keeping the flames locked to her body as she moved?

At times, the fire simulations would run into issues when Olivia’s arms were flailing around. For example, there might not be enough voxels being emitted because of the speed of her movements, or the fire might shoot out in wrong directions.

By setting keyframes on specific parameters within Fume, we were able to tame the behaviour of the simulation so that it would behave exactly as we needed. Using parameters like Wavelet Turbulence in Fume, we also achieved more time-friendly simulations, adding extra detail to low-resolution simulation caches, while preserving the overall motion. We added reflections and interactive light in compositing. So, lots of work was needed for this sequence!

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In another scene, Agatha attacks Havana with one of the acting awards she’s won. What did Switch VFX contribute to the scene?

Production had applied some blood to Julianne Moore’s forehead, face and chest, but it wasn’t enough, and the forehead prosthetic didn’t look real. Throughout the sequence of shots, we added more and more blood and damage to her forehead, and blood spray to the chair and lamp.

David wanted to have the forehead wound look concave, so David Alexander, head of our 3D department, made an appropriate element in Maya. The plates were tracked using PFTrack, with our lead tracker and coordinator, Beau Parsons, making sure the CG element moved properly, because Julianne did fling her head around quite a bit. The CG element was composited into the shot with colour correction, using Nuke, enhancing highlights so it would look wetter and bloodier, and we added extra dripping blood.

Viewing the sequence on a large screen, we realised that the chair Julianne was sitting on was moving subtly with her, so the added blood spray wasn’t tracking properly. The audience would probably never see it, but we went in anyway and fixed it with a gridwarp track in Nuke.

For a scene in which Havana Sagrand (Julianne Moore) is bludgeoned with a movie award, Switch FX added extra blood and gore, and enhanced the appearance of the forehead prosthetic worn by the actress.

For a scene in which Havana Sagrand (Julianne Moore) is bludgeoned with a movie award, Switch FX added extra blood and gore, and enhanced the appearance of the forehead prosthetic worn by the actress.

Many of David Cronenberg’s films contain iconic “body horror” scenes. Was there any sense that you were adding to that body of work?

There was at first, but after seeing the film twice, now I’m not so sure. Maps to the Stars deals a lot with apparitions seen by some very unstable people, many of which appear around that same pool area. The immolation scene seems to come out of left field. There is no gas can or anything that would cause her to ignite as she does. We clearly see the pool, but where does her body go after? So I’m not sure if that scene happened at all, or if it was in Stafford’s head – not an unusual thing for a Cronenberg movie, but it was definitely more subtle than his earlier work.

David is very good at getting under your skin and making you feel uncomfortable, whether it’s with graphic body mutilations, or with the way people communicate or interact with each other with topics that the audience might feel unsettled.

Switch VFX also created a number of set extensions and background replacements. Tell us about the scene in the coffee shop, where you replaced the Toronto exterior with a Los Angeles street scene.

In the script, the location takes place inside Denny’s on Hollywood Boulevard. The interior sequence was shot in Toronto at a coffee shop/diner, on one of the major roads here in the city. A greenscreen was placed outside the window at the curb to allow extras to walk back and forth along the sidewalk outside the diner.

"Maps to the Stars" background replacement by Switch VFX.

It was a pretty straightforward set-up. The foreground plates were shot, with camera information recorded, and then comped with a location plate of Hollywood Boulevard. In order to get the right perspective from inside the diner, we had to manipulate the background plate by resizing the image, creating a few matte painting building elements, and add some vehicles driving by. Also, there were timing issues on the extras walking in the background – some of them had to be removed or replaced.

Another thing we did for this sequence was a continuity fix with a reverse angle on Jerome, which required us to remove a waitress, and make her appear on the angle on Agatha. We also had to add some arm movement to the fry cook – in a lot of his takes he looked frozen, like a still image. We did this by rotoscoping out his arm from another take and compositing it into the hero plate. This sequence was mostly handled by Barb Benoit using Digital Fusion.

What else did you do to turn Toronto into Hollywood?

During the editing process, there were a number of shots where David wanted to add the Hollywood Hills to the original Toronto location. All of them required rotoscoping of the actors and the objects within the frame. Luckily, the shots were filmed outside, and the sky was quite uniform, so we were able to get a rough key for most of it. It did still require a lot of rotoscoping of any fine hair on Mia and John Cusack, as well as moving objects with in the frame.

All the Hollywood Hills shots were tracked using Nuke’s 3D and conventional trackers. The background plates were shot with a still camera in L.A. from a number of angles, because we were not sure which one would work best for the shots until we started putting them together. Also, couldn’t actually shoot where the scenes took place in the script, so our matte painter took the stills and tiled a number of them together to create the correct view.

We had to remove a lot of foreground buildings, the Hollywood sign, electrical cables and so on, in order to get exactly what David was looking for. We replaced all the skies as part of the matte painting process as well. This was then put all together by our senior compositor, Gudrun Heinze, using Nuke.

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How involved was David Cronenberg with the visual effects?

He’s a very technically-oriented guy, so you can have a conversation with him about what steps are needed to achieve these shots, and he gets it. He also knows when to take a step back. I feel he treats his departments the same way he treats his actors – he wants them to perform as best they can, and he knows to achieve that he doesn’t need to direct every single detail. He was very clear in describing what he was looking for, so after he had taken us through it, he pretty much left us to decide how we wanted to execute it.

Most of the shots in Maps to the Stars were straightforward and seamless, so not much was required creatively. However, the fire sequence was very much a back-and-forth process with David, because the outcome was very important to him. As everyone knows with fire and water simulations, you set one up and see what the outcome is, so we had to go through quite a number of simulations before he was happy. Overall, David was a pleasure to work with.

How do you feel about Switch VFX’s work on the show, looking back at it now?

We are very happy with the work. Most of what we did are seamless effects, and they are integrated into the film quite well. Some critics seemed to focus on the fire scene as taking you out of the film because of the clearly CG nature, but considering what was involved, and knowing we had to go this route – and because the scene is very surrealistic and unsettling – we feel that it works quite well.

In this industry, we all wish we had more time to perfect things. But if we were left to do that we would never deliver, because as artists we are never satisfied! We are very proud of the end result, and we look forward to getting an opportunity to work again with such a respected filmmaker as David.

Maps to the Stars was released on DVD/Blu-ray and Netflix on 14 April 2015.

Maps to the Stars photographs copyright © 2014 by Focus Features and courtesy of Switch VFX.