Garrysmod materials and model files are completely interchangable. Reskins and custom models are all over garrysmod.org separately and as SWEPs. Your only problem is that they’re probably hexed, but this can be fixed easily by hexing the models back–no need to hex materials, the model will call for them automatically.
That’s all you need to know. I won’t give you a hexing tutorial, but I’m sure if you extract the HL2 models with GCFScape and open the models with a hex editor (not notepad, errors can occur), you’ll see the differences. Hint: You won’t need to scroll down at all to see the differences. It’s just the name and 4 symbols before it.
Here’s a hex editor for you.
For some reasons many users haven’t been too smart to catch on that almost all games running on the Source engine have materials and models that are capable of being put into other Source games. The reason why you see all these models and skins in garrysmod screenshots as SWEPs is because people like the skins and models, script them in Lua for garrysmod fun, and hex them to not collide with your stock models. Getting these models into your game is only a matter of calling them in a script to appear in-game, or hexing them to replace a model. In short, Garrysmod=HL2.
Here’s a list of interchangable game models I know of
+Team Fortress 2
+The Ship (not all models, judge.MDL will crash your game)
+Half-Life 2: Episode 1 and 2
+Day of Defeat: Source
+Counter Strike: Source
+Zombie Panic: Source
+other games and mods I don’t remember.
I’m just putting this down for those annoying users who keep saying models and skins found on Facepunch and garrysmod.org aren’t similar
when they are.