LiDAR and photogrammetry specialist company Visualskies breaks down its process. A new excerpt from befores & afters magazine.
Ridley Scott’s Napoleon received a Best Visual Effects Academy Award nomination this year. It’s a film that some might not realize contains substantial visual effects work, alongside live action photography and practical effects. Throughout its many battle scenes are digital soldiers in period costume, synthetic props, CG animals and also created environments.
Scanning, LiDAR and photogrammetry were key aspects of on set visual effects work that aided in building these digital elements, while also providing a means to aid in tracking and matchmoving CG creations into plates. On Napoleon, that work was undertaken by Visualskies.
The company employed a dedicated crew, and a range of equipment–even drones–to scan over 100 locations, do more than 3000 cyberscans of people and props, and collect in excess of one million images.
Here, befores & afters learns from Duncan Lees, director of LiDAR at Visualskies, specifically about the LiDAR side of on set scanning, including the equipment used, how scans are processed, and where we’re headed in this field in the age of real-time and machine learning.
Where LiDAR sits in the visual effects world
LiDAR, which stands for Light Detection and Ranging, involves using a laser to measure distances to various objects. The results are used to build up a 3D representation of an object or environment (and the capturing of photographic textures of the same objects or environment can also be used to start digital replica builds). All that data can be a huge ‘asset’ for visual effects studios which might need to re-create the same objects or environments, or place other VFX elements within or on them.
“LiDAR, in particular, is now integrated with a number of other different technologies, but mainly photogrammetry, to create exact measured digital assets that are exact copies of things that exist on set or on location in the real world,” explains Lees, who spent several months working on Napoleon. “It can be the entire countryside, or it can be a wheelbarrow. The way I describe it is where people are going to combine live action shots with CG elements. We create a computer version of something that’s real so that people can use that further down the line in any way that’s needed.”
“In films like Napoleon,” continues Lees, “we are creating digital assets so that no one knows that a visual effects shot has happened. It might be that in front of 20 tents with live action people, that then has to go from that to thousands of tents on a huge landscape with hundreds of thousands of people. We’re helping to create all of those elements accurately, precisely–with correct measurement, correct color, correct textures–so that they can be replicated out, often combining close-up live action shots with wider views.”
Lees adds that, these days, the term ‘LiDAR’ tends to be used as a cover-all term for all things that use light to measure objects, spaces and places. Even cyberscans of actors in dedicated photogrammetry rigs to help build digital doubles, a service that Visualskies also offers, is part of the overall scanning process, even though it focuses on using arrays of cameras.
“It all boils down to coordinate geometry,” notes Lees. “Everything is turned into x, y, z coordinates. LiDAR scanners, photogrammetry, close range projected light scanners–all of this technology is used to create measured data, measured pixels or measured points in space that define a form of a person, or a car, or a sound stage, and we turn all of that coordinate geometry into something that looks exactly like the real thing. Visual effects want a three-dimensional model that loads into Maya or Houdini that is textured properly, is the right dimensions, and then seamlessly fits in with anything that’s been shot with a real camera. That’s what we do.”
Read the full article in the print magazine.
