Previs helps Joss Whedon realize VFX vision for 'Avengers'
Issue: May 1, 2015

Previs helps Joss Whedon realize VFX vision for 'Avengers'

LOS ANGELES — As previs/postvis supervisor at The Third Floor (, working on such Hollywood blockbusters as The Avengers, Iron Man 3, Thor: The Dark World, and Thor, Gerardo Ramirez has plenty to say about the important role that previs and postvis played in Marvel’s newest Avengers offering, directed by Joss Whedon.  


“We knew early on, this was going to be a big film with lots of visual effects and a need to figure out how the story would develop or how to shoot certain scenes. Joss wanted to utilize all the visualization tools we had — previs, mocap, virtual production, techvis — so we knew we were going to touch multiple aspects of this film and help multiple departments.”

According to Ramirez, the previs was a tool used to help the director and other departments — stunts, second unit production, visual effects, etc. — realize Whedon’s vision. 

“When they can actually see something in motion, see this idea and see the way Joss actually is envisioning the concept, it’s a lot easier for them to figure out what they’re going to need to build, what kind of props they’re going to need, what lenses, what angles, it’s a very informative tool.”

Beginning in September 2013 at its LA studio and then moving to its UK offices for the majority of the work, Ramirez says The Third Floor wrapped up its Avengers contributions earlier this year. Shot predominantly on Arri Alexa cameras, with the Phantom camera for the high-speed Pietro shots, The Third Floor relied on its Xsens MVN system for motion capture and on Maya, a familiar tool for the VFX studios, such as ILM.

“We visualized a lot of the major CG scenes; the action scenes” he says, “such as the Hulk Buster sequence, the freighter scene, the South Korean [Seoul] chase scene, the final battle, the party fight, and the early tie-in shot.”

Ramirez explains that the studio was involved in so many areas of the film, “we had part of our team designing one of the action sequences, like the Hulk Buster sequence, with a few artists animating that and we also had a virtual production team, lead by Casey Schatz, that helped scout and rapidly prototype scenes using previs, motion capture and techvis viewed within a virtual camera system. Once the filmmakers found a location or had a design they wanted to construct, the previs team created that location in CG. Then, at their convenience, the director, cinematographer, or any department, was able to come in and hold the virtual camera and basically do a virtual scout and walk around the sets and explore camera angles. That was a very important tool as well.”

Ramirez says that second unit director John Mahaffie used the virtual set heavily, spending hours with the virtual camera to explore different parts of the set, rehearse scenes and stunts, and view them from different camera angles.  “Once he was on-location, he knew that set like the back of his hand,” says Ramirez. 


Explaining that the postvis process begins as soon as the footage is shot and the editors cut some footage together, Ramirez again refers to the Hulk Buster sequence, saying that as soon as they got the plates, and the editors started cutting those together, they would send those plates over to his team, which would put previs CG character versions on the plates.

“It was very important for that sequence because it's all CG action,” he explains. “After they shot empty background plates based off the previs, we would track the plates and then try to use the animation they liked from the previs and place it onto those plates. And that’s kind of the postvis process we did throughout the entire film.”

Ramirez says for a scene such as the “party fight” in the Avengers Tower, where the characters are running away from iron guard legionnaires that were firing at them, “we comped in our CG iron legionnaires in the background and this process helped Joss take a look at the sequence, edit it, tighten it up, and the end result was that anyone in production could see the sequence and understand where it was going. It was helpful for the editor and helpful for the VFX vendors where we would send them our files to help expedite the process on their end.”


Ramirez says their biggest challenge was the film’s early tie-in shot, where “in one continuous camera move, we go from each character. We spent extensive time on this shot. We worked on the previs and then we broke down the shot and took it into techvis and calculated the camera moves. We worked really closely with the second unit director to help plan the actual shoot and figured out things like, ‘this part of the shot is going to be a wire cam,’ and ‘this part of the shot is going to be mounted on a truck’ and ‘this part of the shot is going to be on a motorcycle.’ Once they shot the plates, the next step for us was the postvis, which was also challenging because we had to take many plates and try to combine them into one continuous shot. The filmmakers really finessed the shot until they got it to exactly where they wanted it so when we passed this off to ILM, they knew almost exactly what Joss was looking for.”

Ramirez sums up that with a film like Avengers, “visualization becomes so powerful because it helps make a lot of the decisions. And I mean, Joss, the editors Jeff Ford and Lisa Lassek, and the VFX supervisor Chris Townsend really used this process for showing all the departments, including the visual effects studios, this is a vision we like. On a film like this, with such a tight schedule and of this magnitude, there’s not a lot of time for the visual effects studios to get these shots done. So it’s really important that we had a strong team to be able to work closely with all the departments so there were really good creative and technical roadmaps that were close to what everyone was looking for and expecting.”