Previs: <I>Alita: Battle Angel</I>
Issue: January/February 2019

Previs: Alita: Battle Angel

Based on the graphic novel “Gunnm” by Yukito Kishiro, Alita: Battle Angel is a new animated feature film from 20th Century Fox. Directed by Robert Rodriguez, the film centers on Alita (Rosa Salazar), a cyborg who awakens with no memory of who she is, and in a future world she doesn’t recognize. 

The film is packed with creative characters and sci-fi cityscapes. Here, The Third Floor’s previs supervisor Austin Bonang details his team’s effort to help map out the film’s action sequences and virtual environments prior to production.



What work did The Third Floor contribute for Alita: Battle Angel?   

“We had a team of artists in Los Angeles creating pitchvis, previs and techvis. We also provided some of the postvis. The previs included virtual art department work, where we built previs scenes and models to help develop environments such as the Motorball Chase.  We also visualized props, including the main villain’s claw weapon, to see how those devices might look and how they could work for the story, and we created techvis for camera placements in some shots.”

How did you go about visualizing the unique worlds in Alita? 

“Our source for the previs was mainly concept art from the art department. We also visualized some sets from scratch. Our visualization of the set for the roller chase through the streets, for example, used concept art combined with pieces our artists built to connect the dots between designed set pieces. The ideas and images would then be presented to and iterated with the filmmakers.”



How did the previs help inform the visual action?

“Given the number of CG visuals, previs was useful to understand what the virtual characters would be doing in the virtual environments. It was important to work out the action, as well as some of the core technical requirements of the shoot. There were also a number of complex shots using timelapse treatment or stunts that were explored ahead of shooting and visual effects.”

How did you collaborate with the filmmakers?

“We worked regularly with visual effects supervisor Richard Hollander and with director Robert Rodriguez. Robert was very open and excited to work with previs, and would often create cuts from the previs we had delivered when he had new ideas or inspirations about the shots.

“For the Alley and Underworld fights, we had storyboard animatics to reference that Robert edited and even voice acted. For the Chase scene and dramatic climax scene, we worked from the script with scene descriptions from the filmmakers to shape the scenes closely with them.”



Describe your work on key scenes.

“We worked on two core fight sequences: the Underworld Battle and Ambush Alley. We also visualized the Motorball Chase and the timelapse scene.

“For the Underworld fight, we created an overview of the scene with techvis diagrams to block out with Richard where the characters and stunts would be staged throughout the fight. We also calculated camera distance measurements for a number of shots.

“One of our biggest challenges was really paying attention to real-world physics in the previs. It’s extremely important to convey this believably when working on a film with such fantastical settings and circumstances. Gravity, weight and other real-world factors were always taken into account.

“For Ambush Alley, we needed to find optimal places for staging and cameras within the narrow and tight alley set. We always had the real physical set build in mind so we never cheated the camera through walls to achieve an angle in previs that could not be shot practically. The gag with the ‘Mantis’ woman, Nyssiana, being kicked into the wall was a challenge in timing; it took a while to get that to work as since she needed to leap off one wall and be kicked into another wall 90 degrees to the side, all in mid-air. 



“The big challenge of the Motorball Chase was the short time we had to visualize it. The previs was fleshed out over just a few weeks, without storyboards. The ‘gags’ in the scene were developed with the filmmakers or amongst our team of previs animators even as the environment and the previs animation both continued to evolve. 

“The Timelapse scene was challenging purely by needing to emulate the look of timelapse photography in previs. We had to hand animate camera moves as well as generate animation for separate render passes for sky color changes from day to night, clouds moving, lighting shifts from day to night, environment source lighting, star maps and so on.  This process creates thousands of frames of animation that need to be composited together into single previs shots. 

“With the Underworld Battle, is was especially challenging to visualize the way the Grewishka character fought with his claw weapon, and how he would move in the space given his large size. 

“The filmmakers never wanted him to just stand and fling his weapon so we had him moving, running and jumping while firing his claw. This created a challenge for us to hand key, without a simulation, that physical relationship. One especially challenging moment is the shot when the claw chains are spiraling around Alita as she dives through them. Rigging the claw alone was a challenge for the previs team because the weapon needed to switch from a retractable chain-like control system to a hand with controls for fingers.”
 
What pitchvis did you create for the project?

“The Third Floor created pitchvis for the Underworld Fight and it was my favorite scene to work on! We had the most time on this sequence, so we really could push the look of the previs with nice lighting, shadows, motion blur, and refined animation. The visualization of the scene is almost 1:1 shot wise with the as-aired scene. The film and visual effects team beautifully refined the animation and lighting in final shots, creating the finished models, animations, simulations and FX. It was exciting to have laid so much of the groundwork during previs.”



How did you create a convincing look and animation for Alita for the previs phase?

“Alita is super powered but we had to ground her in reality as much as possible. Taking that into account, it was really fun to develop and test ways for her to move and fight. All of the gags were driven from the standpoint of reality, which was a mandate from the filmmakers from the start. To help with this, we were able to use the Lightstorm sound stages and stunt crew to capture motion for Alita to help drive the previs animation. We took the graphic novel source material into account as well, making sure the moves we visualized worked within the parameters of reality.”

What are you most proud of or excited to see on-screen?

“I was really proud of how closely the previs we created with the filmmakers reflected in the final scene they realized. Also, one of the cool things of previs is that we sometimes are looking not just at how shots or particular scenes of action unfold, but about how the things in the story actually function and work.  For example, in a world of super-powered robots, how realistic should their mechanics be vs. how just purely cool and over-the-top?   

“Everyone was very collaborative and encouraging across the project. We all worked openly together to give and hear ideas. It was rewarding in a creative sense to collaborate on cool gags and fights that would excite the audience, and it was fun to live in that world for a year or so behind the scenes.”