(bright music)

(sci-fi music)

(blasts firing)

I've never seen anyone do that.

Action

[Man] Alright (off mic) in a matter of weeks

we may be called off to find a real battle.

Let's (off mic) man her up to speed!

[Ender] Ohhh!

[Mike] Hi, I'm Mike Seymour from Fxguide.com for WIRED.

In the film Ender's Game, the hero, Ender Wiggin,

needs to orchestrate complex, almost operatic battles

to defeat the threatening Formics.

Earlier in the film, while still

in training in Battle School, a floating space station

that hovers above earth, Ender competes in war games

with fellow students.

These complex battles are ballets themselves,

that had to be choreographed by the director, Gavin Hood.

Ender's Game, like the film Gravity, before it,

has had to solve the problem of floating in space.

They've done this by shooting actors on wires,

but primarily only using their faces.

Step through that gate,

and you're in a Zero-g environment.

Battle School is a great visual challenge.

In this black dome, I feel like I'm out in space,

and of course, when you're making a movie,

you want two things.

You want great characters, and a great story,

and you want fantastic big visions,

especially with a movie of this size.

Run your final simulation.

If I win tomorrow --

[Colonel] You'll be the finest commander

we've ever trained.

[Mike] So why do these films digitally replace

their actors, leaving just their originally filmed faces

on CG bodies?

Well the problem the Director and the Visual Effects

Supervisor had to solve is one of physics and balance.

(adventurous music)

Weightless movement in film is simulated

with elaborate wirings.

The problem is that these rigs need to be pivoted

around the waist of the actor.

If the actor is standing up straight,

this is the correct center of their mass.

The problem is that this would be fine

if the actor didn't have to bend or well,

act really (laughs), but as soon as the actor bends

their body, the center of mass actually shifts away

from the body, and this is something that a wire rig

just can't emulate.

Elaborate tricks are often used to try and solve this,

including, literally, puppeteering the actors, themselves,

but in the end, the solution is often just

to line up the shot on an actor, on a soundstage,

and then fully replace their bodies with digital versions

which can be adjusted to match zero gravity's real physics.

Which begs the question, why not just make

their entire bodies and their faces digitally?

We asked the Director this very question,

and while it is true that Digital Domain,

the effects house, did provide some fully digital

performances, on the whole it is still actually

a lot cheaper to not have to do human faces in CG,

and just remain true to the original performance

of the actor.

Well don't forget to subscribe if you want

more behind the scenes action.

I'm Mike Seymour for WIRED.

[Ender] Two, one, now!