The Terrain Generator is a ROBLOX Studio and ROBLOX Studio 2.0 Beta plug-in that generates a voxel based grid of a combination of different BaseParts to create various terrains and landforms via a very large script. It was added in October 2011 along with the actual Terrain object. The script can build up to 2048 cells in each direction, however the script must be modified to allow the slider to reach that value.
The terrain generator was unveiled at the ROBLOX Rally 2011. John Shedletsky, or more commonly known as Shedletsky, has said through his Twitter that the expected release date for the terrain generator feature would be on September 20, 2011, but it was pushed back to October 7, 2011 where it finally released.