Models are contained in files called MODELS.ZAR (There are multiple folders with MODEL.ZAR. Each Model.zar contain models specific to the type of folder, eg weapons, or level folders)

Model are given the internal extension .tif
.tif Model format:

03 02 00 01 04 80 XX 6D
{2ByteSignedIntegerVertexes(X,Y,Z)+2ByteSignedIntegerNormalMappings(X,Y,Z)+2ByteSignedIntegerTextureMappings(U,U)}
02 01 00 01