大片扫描：使用LIDAR为Joker和John Wick

作者：约翰·阿什比

约翰·阿什比（John Ashby）是LIDAR的主管Aura FX，为电影和游戏行业提供现场数据采集服务。阿什比（Ashby）曾在好莱坞大片工作（包括）JokerandJohn Wick: Chapter 3 – Parabellum, capturing 3D scans of film sets and locations. The captured scan data are used in many ways during film production, especially for creating VFX (visual effects).

With time pressure one of the main challenges of the job, Ashby uses aLeica扫描仪P50long-range 3D laser scanner for high-resolution, fast scanning. And with lots of data to juggle, he usesLeica Cyclone软件，用于轻松处理大量扫描。

The benefits of reality capture in the film industry

Using LiDAR and other laser scanning technologies is helping the film industry to increase efficiency in production and post-production, and at the same time, create more realistic visual effects. A scan of a film set or location provides an accurate record. which can be used to help match camera angles. This ensures continuity and sets the foundation on which to build any virtual assets, for example, a digital set extension.

使用激光雷达改善VFX的现实主义

Having a scan as a reference point helps VFX teams create more seamless effects. Previously, footage of a film set would be used to make a virtual recreation in 3D. To add realistic-looking effects, the technicians would need to match the same camera angle and motion as in the original shot (‘match moving’). Without laser scanning crews would take detailed measurements but couldn’t achieve 100% accuracy. By capturing the entire 3D world of any shot, LiDAR and laser scanning combined offer a precise map from which to work.

Ashby gives an example from his work on小丑。“我扫描了很多集,包括亚瑟的分开ment, and the TV set for the Murray Franklin talk show, which I scanned because there was all this CG blood that had to get added in post and this allowed them to get a perfect camera track of those sets.”

Fast scanning speeds are required for scanning in a frantic environment

速度对于设置扫描至关重要；凭借大型船员和巨大的运行成本，数据收集不会延迟电影制作。：“这全是关于您在最快的时间内可以得到的最多数据，而无需支撑生产，” Ashby解释说。

When working onJohn Wick 3: The Continental,Ashby had only four hours to scan and photograph a major location. “The building for the shoot-up of the Continental was One Hanson Place in Brooklyn which is huge. It was just a pure race against time.” Ashby needs to get as much data as possible and to be prepared to stop and start scanning to fit around filming, sometimes even grabbing scans between shots.

阿什比（Ashby）在集合或位置上解释了他的激光雷达扫描过程，“我倾向于快速闪电仪，以获取“注册”。这只是许多快速的低分辨率扫描；只是我知道，在最坏的情况下，我对环境进行了完整的注册。然后，我将四处走动，从不同的“电台”进行豪华扫描……提高分辨率和采样质量，以使其更遥远和反射性。”这是Ashby使用ScanStation P50的地方，他发现它的速度是他用于较短射程工作的其他激光扫描仪的两倍。

“The way I have the Leica Geosystems scanner setup is at a resolution of 1 point per 0.6 centimetres at 10 metres...you’re capturing more data in a lot less stations,” Explains Ashby. “The data from the ScanStation P50 is unbelievably clean – it’s really fast.”

使用激光扫描来改善连续性

通过创建拍摄环境的虚拟3D版本，LiDAR扫描使您可以更轻松地从不同角度看到对象的位置，并确保事物在应该的位置。Ashby解释说：“ LIDAR真正帮助您做的是，当您从不同的相机角度进行多次拍摄时，您可以跟踪LiDAR数据的所有内容，并将所有相机捕捉到同一世界空间。”“这意味着，如果您将某些东西一次放在3D空间中，它将在所有其他镜头中在相同的3D空间中。”

使用一个场景的示例小丑，阿什比（Ashby）谈论了一个有很多削减的场景。扫描帮助技术人员从不同角度匹配CG血液，“这意味着射击中的血液与Shot B中的血液完美地排列。”

Easy-to-use software is essential for checking high numbers of scans

The need to stop and start scanning can complicate the process of registering scans together. “All your scans can get really jumbled around. So a good logging system is key and then it’s much easier when you have to manually align your scans after,” clarifies Ashby.

Ashby uses Cyclone software for post-processing and likes the amount of control that it allows for manual alignment. “The Cyclone software package is very fast for that. You just overlay them [scans] on top, you quickly just line them up and that’s pretty much it…You can get through about 80 scans in about a couple of hours.”

在其他行业如建筑或基本ring, a scan would be used to create a highly detailed 3D model of the environment, however, in the film industry an OBJ (polygonal mesh) is often the preferred output, containing all the detail that’s required; “OBJs are pretty unbreakable as a format and generally the most requested deliverable.”

Ashby’s job is then complete as he delivers the scans to others working on the production, “I typically hand off everything to production or a visual effects studio.” Having packed his laser scanners into flight cases, the LiDAR supervisor is ready to head off and use his Leica Geosystems laser scanner on the next set.

基于：激光扫描为小丑和约翰·威克（John Wick）