"Garry's Mod" is a first-person physics sandbox game that allows players to play with the physics in the Source engine, the game engine created by Valve to run games like "Portal," "Half-Life 2" and "Team Fortess 2." The game has no overarching goals or story. It is basically an intensely complex, digital Lego set. Some players may wish to make their player model invisible. There is a simple way to do this.
Download the AlyxFakeFacotry NPC model.
Unzip the AlyxFakeFacotry NPC zip file using a decompression program such as WinZip, WinRar or UnRarX.
Copy and paste the files in the AlyxFakeFacotry NPC folder to your "addons" folder in "Garry's Mod."
Open the model menu in the game and spawn the FakeAlyx model. This model is invisible.
Select your model manipulation tool, then right-click on the FakeAlyx.
Reload your own model. You will now be invisible.