Patch

How it works

The #patch materials folder is located at migi/csgo/materials/#patch/ and makes MIGI create patched Pak01 files to this location.
Essentially, putting existing VMT files from the Pak01 to the same location but instead of the standard csgo/materials/ you'd put them in csgo/materials/#patch/, will transform the originals to include that file and lose their original parameters.

Example

You want to test modifications on pak01/materials/models/chicken/chicken.vmt without rebuilding MIGI each time.
Simply copy that file to migi/csgo/materials/#patch/models/chicken/chicken.vmt and this file will be loaded instead.

While in this folder, those VMTs are considered normal VMTs by the game, so path rules for VTF files still apply, in other words: #patch is considered as an actual folder.

Once in-game you're free to modify those materials and execute mat_reloadmaterial yourmaterial at will, as you would with any custom material.

Again, in order to patch materials, you must build after adding your new files and before entering the game.

More information about the Patch "shader" used to allow this feature: https://developer.valvesoftware.com/wiki/Patch