VSI
VSI (short for Valve Stripping Information) is a model-related file format that appears to take VTX and VVD files and remove the LOD data, for Xbox 360 versions of Source games. This is probably done to save disk and memory space. Hypothetically, it could be used on PC versions of Source (not recommended).
Contents
Games
File format
Files
Links
An Xbox-oriented variation of the standard MakeModels.cpp