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Stephane Ceretti and the VFX of ‘Doctor Strange’

The action-adventure film’s overall VFX supervisor discusses visual design, fractals and practical effects used on Marvel’s latest hit.

Marvel’s latest comic-inspired film franchise, the mind-bending and riveting Doctor Strange, has found a receptive international audience, quickly heading towards $600 million at the box office in less than three weeks in release. Managing the film’s visual effects was overall VFX supervisor Stephane Ceretti, an industry and Marvel veteran, having held similar roles on Guardians of the Galaxy (2014) and Thor: The Dark World (2013) as well handling various VFX supervisor and digital artist duties as far back as his original work as an animator on Batman & Robin (1997) at the French studio, BUF. AWN’s Spencer Fawcett recently had a short sit-down with Ceretti to discuss his work on Doctor Strange.

Spencer Fawcett: Much of the visual effects are very ‘Inception-esque’ in design, but go one step further. What was the visual design philosophy for the effects work?  

Stephane Ceretti: We looked at Inception early on but it’s a very small part of what we’re doing throughout the film. We looked at optical illusions, Escher and forced perspective, a lot of work with 3D fractals, etc. We all had a game on our phone called Monument Valley that was all about changing perspectives. We referenced a lot of films and photography as well. We started from Inception but we wanted to push it a little bit further from there in terms of, “What does the VFX do to that action scene? What does a chase look like in that world? How do you make it relate to magic as well?” We took it crazy when we went into kaleidoscopic imagery. What you see in the trailer, with the folding city, is just the beginning of what we were doing in Doctor Strange. I would say that Inception was the spark but the film is the fire.

SF: There is a lot of glass and fractal visual effects going on in Doctor Strange. Was that more difficult work than normal for the VFX artists?

SC: When you start to play with fractals, it’s very mathematical so its process intensive. But you cannot choreograph it very well because it reacts in a very procedural way. So, with this film, we had to create the different deformations, change of shapes and the use of fractals that we’re doing. You need to do that to direct the scene and have what you want in the shot. And because we had four different visual effects vendors working on the film and all working together to match together, they worked as a group to figure out the best way to go about choreographing and controlling the fractals for what we wanted.

SF: How much of the budget was spent on visual effects?

SC: [Laughs] I can’t really tell you that. I’m going to not answer the question for two reasons: I don’t think it’s that relevant and I don’t know what the overall budget of the film is. But as you can imagine, it’s a significant part.

SF: What were the main software tools used for the visual effects work?

SC: I can’t talk for the vendors because they have their own tools and procedural software. They have their own stuff like destruction tools. Primarily they used Maya and Houdini, especially the latter, for this film.

SF: What type of practical effects were used alongside and merged with the visual effects?

SC: Obviously when you go to other dimensions, there’s not too much you can do in terms of practical effects. But there’s a lot of destruction that we had to do in Hong Kong. The practical effects guys created a rig for us to put Benedict Cumberbatch in to do tumbles and stuff like that. They had to create that equipment when Benedict made his journey through into the other dimensions. It’s kind of a film within a film. A lot of it was previs combined with motion control cameras for that sequence. They did the car crash, which is a big moment in the film. And for the sequence when they were running on the sides of buildings in New York, they built these large-scale treadmills on top of motion bays.

SF: How big would something like that be on-set?

SC: It was 6 feet wide and 8 feet up and was a collaboration between the SFX guys and stunts to figure out how to get the shot. It was like a puzzle.

SF: Who did you bring in to handle the visual effects? Where was all this work rendered? 

SC: I work in collaboration with Marvel to get the effects done by these VFX companies. We had four main vendors: ILM, Framestore, Luma, and Method, which were pretty much all over the world --Australia, UK and the U.S. We also had some people in Berlin and India. So, it’s rendered everywhere, 24/7 all over the world. We went to specific studios for specific work. Framestore is better at animation for the cloak of levitation because it’s a character in the film. ILM is very good at big environments and big effects so we went to them for New York and Hong Kong. We kind of cast the visual effects companies to do the work.

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