When I poster this at the time there was a video showing clips of this that isn't showing now, but that clearly shows all the main cast acting together, so the blue screen studio wasn't empty.
I think this is the first time anyone has released the entire film in its raw state. Avatar had three versions on the disc, theatrical, extended and an even longer cut but the extra scenes in the third version were still in a raw animatic state.
Sin City also released the full film in its green screen version but sadly, it was sped up. The entire film runs through in just twelve minutes.