There is only one file type that uses the .V3O extension:
Emergency 3 and 4 Model File
Three-dimensional model used by Emergency, a game where players manage emergency situations and rescue scenarios; contains a 3D mesh, which is made up of vertices and connections in a 3D space; may be painted with raster graphic textures.
V3O files are used for storing models of vehicles, firefighters, policemen, buildings, and other game objects. They can be edited using the built-in Emergency Editor, or with the open source Zmodeler application.
NOTE: V3O files were introduced with the 3D engine in Emergency 3. They are used by both Emergency 3 & 4.
Updated: June 26, 2010