Terragen2 from Planetside is software for rendering and animating realistic natural environments. You can create anything in your mind from simple environments to complex world just with one piece of software. Terragen2 allowed to create director Zack Snyder's complex environment for his fantasy Sucker Punch. Planetside cooperated already before with Prime Focus on his Tron:Legacy.
„Unlike many other tools that are often limited to use in static matte backgrounds, Terragen 2's powerful procedural capabilities and production-ready renderer allowed for fully realized environments which could be explored and rendered to full motion sequences, including animated clouds and other elements.“
A small showcase of the movie and Terragen2 you can see below.
Source and full article: Planetside