Sandra Bullock in Gravity
The actors, Sandra Bullock and George Clooney, were filmed acting inside a light box that had projected from it the correct environment the actor was meant to be in. Thus, if the actor was meant to have the earth providing bounce light from their left, on the screen on that side of their body was a giant earth image, digitally controlled and correctly aligned.
« Here, the light box LED panels showing the interior of the space station providing the correct lighting around the actor. »
The light box, resembling a hollow cube, stood more than 20 feet tall and 10 feet wide. The interior walls were constructed of 196 panels, each measuring approximately 2 feet by 2 feet and each holding 4,096 tiny LED lights.
“The actor’s cage inside the light box”
It was based on the technology commonly used to put massive images on screens behind rock bands or at sports grounds. “Each pixel is made out of an LED that we could control,” explains Webber. The lights could not only project light, but also varying colors, and the lights could also be programmed to move at any speed.
“What the actors saw”
As its name suggests, the purpose of the light box was to cast the appropriate illumination on the actors inside, no matter where they were or how fast they were moving in relation to the light source.
« The IRIS robotic camera rig outside of the light box »
The light box walls could also be moved and were at times placed on robotic arms. To have the actor ‘fall’ towards the camera, the actor would not necessarily move but instead the camera would fly towards the actor, with the aid of the IRIS robotic camera rig from Bot & Dolly.
Below is a diagram of the side and top view of the camera arm that would move towards the actors to simulate them flying at the camera on screen.
This combination of flying the camera and lighting Clooney and Bullock by the light box would then allow an accurate performance to filmed of each of the two lead actors. But for a shot where they were in their suits, only their faces would be real, the rest of their bodies, suits, hands/limbs, environments etc were all digital and fully 3D animated.