Like "Gravity," though, DD needed to come up with its own integrated LED lighting system to match live-action and virtual environments (though set against more conventional green screen) to simulate the physics.
Everything was wired through a computer system so it could be customized and could change the mood within that space. But they had 4,500 individual lights on set. They used an extensive LED lighting system, and the cinematographer's team devised schematics for thousands of lights wired through a dimmer board and controlled by a computer system that could lower, raise or pulse the lights.
Because DD had developed CG versions of the actors' flash suits and re-created the lighting environment digitally, they were able to keep the actors’ faces from the live-action shoot and replace nearly all of the body motions with digital doubles. In the end, the only real elements in the Battle Room are the actors' faces and the gate where the Launchies enter.
Later on, content displayed in the sim cave is a volumetric holograph that allows Ender to control his POV of the game. As he moves through the grid, the graphics (created by G Creative and Goldtooth Creative) are entwined with his reality. The final battle is the source of the most compute-intensive, geometry-heavy effect sequence DD has ever created: more than 27 billion polygons in a single shot alone.
"The world that we create -- the battle, the ships shooting at each other and colliding -- is fairly realistic and you believe you're there. But we had to immerse the kids into it as if they are in this giant hologram and Ender can control his point of view as he's commanding this fleet."
As Butler says, "Ender's Game" is virtual production at its best: "A marriage of practical stunt work with post manipulation of computer graphics."