You can re-compile it.
You need:
GCFScape
MDLDecompiler
Notepad
Source SDK with UPDATED content.
Do:
FIRST: set your sdk engine to 2009, and game to Half life 2.
http://www.1337upload.net/files/2010-07-23_20.51.18.png
Then start with opening C:\Steam\Steamapps\source models.gcf with gcf scape.
Browse to \hl2\models\Humans\Group01\Male_01.mdl and extract all of the files that start with ‘Male_01’ to your desktop (anywhere really).
Now use the MDL decompiler (with ALL of the little boxes unchecked) to decompile the model. You will get a bunch of files, all that matters is the .qc.
Open the .qc file with notepad, and edit these two lines to your liking:
$modelname "folder\modelname"
$cdmaterials "folder\modelname"
in this example, we will compile your new citizen model to
“garrysmod\models\mymodel\Male_01.mdl”
and make it search for the textures in
“garrysmod\materials\models\mymodel\citizen_sheet.vtf”
So our new code will look like this:
$modelname "mymodel\Male_01.mdl"
$cdmaterials "models\mymodel"
Now, save and drag your new .qc file onto
C:\Steam\steamapps\lolname\sourcesdk\bin\ep1\bin\studiomdl.exe
a black box should appear and WHITE text should flash across the screen for a COUNTABLE amount of time. This means your model has compiled successfully and it can be found in your half-life 2 folder.
now that your model is done, it needs textures! Drag your skin WITH the .vmt into hl2\materials\models\mymodel*, now this won’t make it work, you need to open the .vmt with notepad, and edit the lines to direct the game to the correct textures, for example
$basetexture “models\humans\citizensheet.vtf”
would be changed to
$basetexture “models\mymodel\citizensheet.vtf”
Then you are done, copy the model files and textures into gmod and enjoy.
Edit: Tell me if i messed up somewhere, I made this pretty quick and vague…