“I, Robot” tackles the “Three Principles of Robotics” head-on *Note! Contains spoilers.

robot synthesis

The problem was that it was necessary to create a material called a clean plate, which erases the robot actor and fills in the gaps. The robot stand-ins were wearing green full-body tights(*5), and were erased in the same way as green screen compositing. However, because the NS-5 is slimmer than the average human body, the holes could not be filled even when a CG character was placed on it.

If we were to use conventional VFX techniques to film a scene involving Detective Spooner and Sonny, we would first use motion control to film the two actors' performances, and then film Will Smith alone with the same camera trajectory to create a clean plate. However, based on their experience working on Gollum, the staff at WETA Digital were concerned that Will Smith's performance alone would be unnatural. Also, there would be a difference in the way the light reflects off the actors when there are two actors and when there is only one, so the composited image would look fake.

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For this reason, no separate shots were taken for this film, and the holes in the screen were filled in with a huge amount of painting. This was where Nuke , a compositing software developed by Digital Domain, came in handy. By tracking the areas hidden by the robot stand-ins, creating 3D geometry for the background, and mapping the original texture, a completely clean plate was achieved. This work required 10 months and 35 sets of Nuke.

The Encoder Cam was also used for the first time in a film. This is a system that tracks all the movements of the camera rig, crane, dolly, etc. in 3D and can be composited with simple CG in real time or reflected as motion data for VFX work.

*5 The NS-5 was designed so that its chest would glow red when it was in combat mode, and the actors playing the robot had two lights attached to their nipples so that the glow would be reflected in the environment and on the other actors playing the robot.

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