Image courtesy of HBO

HBO’s Westworld turns to Unreal Engine for in-camera visual effects

Ryan Mayeda
HBO’s hit sci-fi series Westworld explores the technological landscape of the near future, from lifelike robots and advanced artificial intelligence to autonomous vehicles and the blockchain. In season 3, showrunners Jonathan Nolan and Lisa Joy and VFX Supervisor Jay Worth also turned to futuristic techniques behind the camera, with help from Unreal Engine.
Always eager to push the limits of the latest production technology, the production team had been brainstorming about how to leverage in-camera visual effects and virtual production processes into the series since the show’s first season. Because the show is captured on film, incorporating the real time performance of Unreal Engine required an extra level of planning and customization. 
In Season 3 of Westworld, the iconic City of Arts and Sciences complex in Valencia, Spain stands in for Delos headquarters. Exterior shots were captured on location, however the interior shots that the Westworld creative team envisioned – with the elaborate complex seen out the window of Charlotte Hale’s (Tessa Thompson) office – were impacted by physical space limitations on set. Epic Games, Fuse Technical Group, Profile Studios, and Spanish-based VFX studio El Ranchito stepped in to help HBO create the desired environment on a 50 by 22-foot LED wall on a stage in Los Angeles.
Epic worked closely with El Ranchito, who captured photogrammetry of the City of Arts and Sciences and recreated it as a dynamic Unreal Engine scene; Fuse Technical Group, who handled construction and integration of the LED wall, including mapping of the scene through Unreal Engine’s nDisplay tool; and Profile Studios, who managed streaming the Unreal scene to the LED wall and the camera tracking.
Hale’s office was designed to have imposing floor-to-ceiling windows that overlooked the main artery of the City of Arts and Sciences complex. Using the LED walls and Unreal Engine for real-time in-camera visual effects enabled the Westworld team to capture physically accurate lighting from the environment coming through the glass, with accurate reflections on the sleek interior furnishings – all with the right parallax as the camera moved throughout the scene.
Image courtesy of John P. Johnson/HBO
“Using an LED wall was the perfect solution to many of the challenges faced on set, which was mainly a lack of available space to get the camera angles desired in this limited interior,” explained Connie Kennedy, Head of the LA Lab at Epic Games. “We were able to use the LED wall to track the camera angles needed, in the limited interior set on stage. Another unique challenge was optimizing this process to work with film, which is Jonathan’s preferred way of shooting. Fuse Technical Group was able to source hardware that allowed us to sync the shutter of the film camera to the content on the LED wall.”
The unique needs of the Westworld shoot required some custom optimizations from the Unreal Engine team including a rotated render output feature for LED walls. This is now available to everyone in the current Unreal Engine 4.25 release.

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