This plugin is included in xFix! It is recommended to use this new plugin over this standalone one!
https://forums.alliedmods.net/showthread.php?t=347457
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By default, HL2DM uses 1 set of footstep sounds for all materials walked onto. This plugin provides per material footstep sounds like in Half-Life 2 games. The only limitation is with displacements and models. Sourcemod will not fetch the material name on anything that is a displacement ( returning *DISPLACEMENT* rather than the material name ), which will play the concrete footstep sounds ( default sound ). Standing on models will play the surface sound of the brush beneath it. Both issues are considered minor.
To fully fix those two minor issues would require compiling custom server binaries. It is possible, but will take more time.
Please note that those sounds are processed server side, not client side. It is not possible to make those sounds client sided without creating an entirely new MP Source mod.
The plugin does not have any commands at all. I made it for myself only, but since I really do not play much, if at all, have at it.