Supervising Guardians of the Galaxy VFX

(Interview performed in February 2015 for Seekscale company, a cloud rendering startup)

Let’s face it: just like Peter Quill ship under blacklight, a blockbuster VFX pipeline can look like Jackson Pollock painting. In addition to great punchlines and awesome characters, Guardians of the Galaxy is also one of the most ambitious movies to date in terms of VFX shots complexity. Several vendors worked on the project, and Seekscale interviewed Stéphane Ceretti, VFX supervisor with Marvel, who oversaw and coordinated the vendors during movie postproduction.

– 95% of the movie contains visual effects. As a VFX supervisor, is it much different than supervising, say, a 40% visual effects movie?

Yes, the workload is really different. In the end it all depends on how complex the shots are too. But on Guardians not only the show was stuffed with VFX they were also pretty complex on average. And the post period was pretty short for a movie of this scale.

– In AWN interview you say that you were involved in artistic work to get Groot and Rocket right with Framestore and MPC. Was your job more artistic, more technical (pipeline coordination etc), or both?

On my side at the studio I would say it is a mixture of the two, but I get very involved in the artistic side of things, and the technical aspect is something I discuss a lot with the vendors but not too deeply.

– You worked with roughly 13 VFX vendors, what were you criterias when picking houses?

We try to match the needs of the movie with what the vendors are the best at. By picking our 2 main vendors on the show, Framestore and MPC, we allocated what we felt was the best match for both facilites. We do the same with the other vendors, trying also to balance budgets and capacity across the board.

– You used previs a lot during production, how can you previs shots before they’re made? Is it some kind of real-time “quick and dirty” renderer fed with concept art and animation?

Previs was actually pretty extensive and detailed. We needed that level of detail to get the right sense of the rhythm of the scenes and also to show the actors and the crew where the CG characters would be, and what they would do. James Gunn, our director, was very precise about all the shots and he drew a lot of “thumbnails” images that got used to create storyboards and ultimately the previz for the show. James was very deeply involved in every steps of the process.

– MPC created Groot while Framestore created Rocket. Why the decision to pick 2 different VFX houses for characters that interact with each other in so many shots?

We had to split them because of the complexity and the amount of work that was required in the amount of time we had. That said, we did not share shots between the facilities. Each facility shared their character/setup/rigs with the other so they could animate both rocket and groot in their sequences.

– How did you have MPC and Framestore likely very different pipelines to play nice with each other? Was there a specific team to develop interfaces and protocols?

We worked very closely with both of them and made them work together so they could share as much information as possible. It was key to everybody’s success and the success of the movie. We needed them to constantly work together to ensure that the smallest details got shared and discussed, from rigging, modeling, texturing, simulation and animation characteristics .. It was a very important part of the process.

– In terms of pure bandwidth between the 2 facilities, how did that work out? Were assets synced in real-time, or in batches?

No, once an asset is approved it is passed on to the other vendor. Sometimes there is revisions but we try to avoid it as much as we can. Rocket and Groot had quite a few revisions as we found out specific things we needed to correct during the animation process, but we always try to avoid too many back and forth.

– In terms of rendering, did you standardize the renderer for the project, to avoid the risk of having inconsistent looks between frames? If not, was there a team to erase those artefacts?

Nope, MPC uses renderman, and Framestore uses Arnold, two very different renders. So shaders could not be shared … But we shared “reference” lighting setups to be able to compare turntable “apples to apples” between the 2 facilities. It was a tough process but we learned a lot !

– Do you have an idea of the approximate size of the render farm that was used for this movie?

Not really, you should ask MPC and Framestore for these details. I assume … HUGE ! And then we had all the other vendors as well 🙂

– You chose to have no mocap technology and do Rocket and Groot in full CG. One person was on stage so that actors know where to look at and talk to. Did we just reach the tipping point where full CG is better than partial CG which sometimes hinders actors performance on-stage?

I think it all depends on the project really, on what you want to do with the characters and what is their interactions with the other characters. There is never a “blanket” answer for everything.. Every case is slightly different. But I think we have proven that full CG characters can be in the middle of “human” characters and the audience isn’t questioning it, and they relate to the CG characters as much as they do for the real ones.

– Marvel likes changing shots at short notice, and has a process to track all changes down. Could you detail this further? Is it software that connects to studios pipelines, or a totally independent configuration management system?

It’s just a lot of hard work and a lot of people coordinating and checking everything constantly. We analyse the cut every week for changes, omits, additions, etc and then we act accordingly, letting the vendors know, getting them the information. It’s in an ongoing process that needs to happen very regularly to make sure we are not missing something. We have an extensive database in filemaker for the show that helps us track all these information as well as all the work done by our vendors. It is essential that all information be kept and updated as we go.

We have a big team of very busy coordinators who take care of the notes and making sure everything flows between us and the vendors. We are not directly connected to the vendor studios but we share information through filemaker or excel. And we have daily sessions with them remotely with Cinesync and Skype which allows us to review their work constantly all over the world. Deliveries are made using our secure transfer system called signiant.

– I heard Marvel has a IT security framework distinct that MPAA. Is there a particular reason for that? How do you make sure that assets sync between so many vendors enforce your standards in a consistent way?

They take security very seriously at Marvel, and vendors are going through a vetting process to be able to work on our shows. We just want to make sure nothing goes out before it’s suppose to be going out.

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