After the countless days staying up and reading through the very minimal amount of information we have on .HFS files in these forums, i decided to shed some light on these files. So without further ado here you all go.
What is an .HFS file?
Hierarchical File System or .HFS, divides a volume into logical blocks, These logical blocks are then grouped together into allocation blocks which can contain one or more logical blocks depending on the total size of the volume
Technical enough for you? i thought so. now what can you expect to find inside of these "Logical Blocks", well they are anything from Material, Texture, Animation, Bounding box, Hit box, Mesh, files.
Files and what they do
Well you could just take a stroll over to google and search this up, but for the sake of this being an info i will supply you the basic knowledge of all the file extensions.
.VMT
A material is a .vmt ("Valve Material Type") text file that defines a two-dimensional surface. It contains all of the information needed for Source to simulate the surface visually, aurally, and physically.
.VFT
The Valve Texture Format (VTF) is the proprietary texture format used by the Source engine.
VTF files are just one layer in the Material System. VTFs ("Textures") can only be applied to Geometry via a VMT ("Material") File. VMTs can assign several VTFs to the same surface, and specify which Shader and Shader Parameters to use when rendering the textures.
.PHY
PHY is the extension for Source's proprietary collision model data format. It stores data for the rigid or jointed (ragdoll) collision model used by the MDL. In addition, it stores some $keyvalues about a model such as which gib-models to use if destroyed
.VTX
VTX is the extension for Source's proprietary mesh strip format. It stores hardware optimized material, skinning and triangle strip/fan information for each LOD of each mesh in the MDL. Currently it is found in .sw.vtx (Software), .dx80.vtx (DirectX 8.0) .dx90.vtx (DirectX 9.0) and .xbox.vtx (XBox) flavours.
.CFG
cfg files can be found everywhere and are not specific to Source. It is an abbreviation of configuration.
In Source games, a configuration file can be executed to perform a list of console commands. CFG files can be written in any other plain text editor. To create one, right-click the blank space in a folder, and go to New>Text file. Rename it to myconfig.cfg or whatever you want, as long as it ends in .cfg. You can then open it in your text editor and put commands in.
Theres some light of what you are looking at as you scan these .HFS files.
What was the point of this thread?
Simple to give people the knowledge of the game engine, and some of its files. and to contribute to the community, Its and info thread, what more can i say.