during development a large, on-rails prop was used to make the roosevelt hotel seem taller, so that the hotel would remain consistent with the shots filmed in-studio instead of on the hotel itself. during the scenes where nick is running along the sides of the hotel, extra floors were added during post-production in order to save the need for a second attachment. in post-production crowds were edited in from other shots so that the crowds would appear consistent throughout the film. the lead actor, sam worthington, admitted during interviews that he had a fear of heights that he had to tackle during recording of the film.