Can't find materials.cs, trying to make a skin

I've looked through the fullsize.zip folder and I found the fullsize.jbeam, fullsize_s.dds and fullsize_d.dds but I can't seem to find materials.cs? Am I doing something wrong?

 

Materials are in json now, IIRC

 

If you Haven't solved it yet use this!
I Believe the fullsize uses This Temp
Else use This Temp

Simply Create a new txt doc & call it skinname.materials.json
In notepad++ Press CTRL+H & replace "skinname" With the name of your skin. Then "carname" With "fullsize"
Go here and Grab a UUID (Not necessary But Recommended). Replace Your UUID With the "UUID"
Save it and You Should Be Good!