Initial development focused on creating a decayed New York. Digital artists removed signs of human activity in the live-action plates, including any electrical device. They then added aging and weathering to the cityscapes. 

The team gathered a wide range of documentation on the subject. "Quite by coincidence, during postproduction, the book The World Without Us by Alan Weisman was released," Sirrs adds. "It explored a scenario very similar to the setting of the picture -- what if all the people in Manhattan were suddenly gone? The general message there was that the supposedly rock solid city of concrete and steel would actually start to decay quite rapidly. For example, without electric pumps constantly removing water from the subways, they would flood within a matter of days. Building foundations would be become waterlogged, and buildings themselves would probably start to collapse in the space of a few years... "

The first step was to remove any sign of human activity in the live action plates. This included moving elements, such as vehicles, pedestrians, people behind windows, but also any electrical device, such as traffic lights, billboards, etc. "We then added all the aging and weathering to the cityscapes," says Smith. "The textures were created using Photoshop or Cinema 4D and re-projected in Maya and RenderMan onto low-resolution geometries corresponding to the live-action buildings. For some of the locations, we were able to use a lot of CG city props models that we had built for the Spider-Man movies, including lampposts, mailboxes, etc. After a cityscape had been aged and weathered, we then added grass and weeds all over the place. The grass was created using our hair pipeline, while the plants were done with a pipeline that we developed specifically. The weed program would procedurally grow 20 different types of plant, with 20 different additional leaves and flowers species, each one of these having many variations. The structure of each plant was built procedurally, and leaves and flowers would be randomly selected. All this required a tremendous amount of very detailed tracking."

Two locations were entirely rebuilt in CGI: Times Square and the City Port and adjacent Brooklyn Bridge. The landmark bridge was recreated as a heavily detailed model: a geometry far too cumbersome to be broken apart in a simulation. To create the missile hit and bridge destruction, the team used a very simple version of the model built in Houdini. A simulation provided the basic movement and weight of the larger pieces. Then, the simulation was applied to the high-resolution model, allowing it to break into many different pieces. In addition, the team added dust, debris, fire, explosions, created in Maya and Houdini.

"In hindsight, I think we may not have gone far enough with the look of abandoned New York," Sirrs admits. "During production, we strove to find a feel of nature returning to the city but without it looking too apocalyptic. We wanted to audience to sense that Neville was the last man alive in a city that was both familiar and tangible, but one that was also filled with a new beauty."