engine vs data

[roboticmehdi]

I want to finally understand how half-life 2 works with respect to files and how to separate ENGINE vs GAMEDATA. Can someones explain me please? From what I understand exe and dll files must be related to engine, cfg files tell engine the configuration, and others must be game data files. (I am talking about unpacked game system btw, no vpk files)

This is what I think I believe so far, if not mistaken:

files under HL-2 are engine. files under HL-2/bin are engine. files under HL-2/hl2/bin are ...? no idea.
what about shaders folder?
expressions, maps, materials, models, resource, scenes, scripts and sound are game data I believe?

and what about HL-2/ platform and reslists ?

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I am trying to understand how half life 2 engine works systematically.
Want to be able to use version X engine to run game with data of version Y, for example. And I believe first step in modding is understanding how this works.

[Evan]

The only thing I know about modding HL2 is the custom folder, vtfedit, gfscape