L4D2 Materials don't work.

I extracted the files and everything from L4D2’s .vpk, and also made the .sw.vtx and that other stuff needed, I copied the models folder in the materials/models, and I tried two things.
I pasted all the folders in the L4D2 Models folder in the GMod models folder.
I pasted all the folders in the L4D2 Models folder in materials/models/Left 4 Dead 2
Neither of them work, all props are invisible. Anyone know what’s wrong?