Welcome to the "CryENGINE 3 Developers" group . The CryENGINE 3 Developers group is all about creating levels, mod, Total modifications, addon's, machinima videos, Indie games, using Sandbox3 for Crysis or using the free standalone CryENGINE 3 SDK tools.
From Crytek site:
You are the director! Learn more about our efficient tools that enable the fastest development of game environments and game-play available on PC, PlayStation® 3 and Xbox 360™. Experience our “What you see is what you play” and our “Live Create” features enabling real-time editing of multi-platform game environments simultaneously both in 2D and true stereoscopic 3D. Cross-platform development has never been so easy!