This guide is a work in progress, sections describing different types of mods will be added over time.

First and foremost, locate the game's Steam install folder.
In it, you'll find the prep.exe script. This is the main modding tool, and is used to build and upload mods.

Secondly, locate the game's AppData folder at %localappdata%/.uoc2/.
The _packages directory located here is where all your mods will be stored locally.


The game consumes mods in the form of packages. A package is a directory containing some assets. In the game's installation folder is the base package (_packages/base).
This package contains all of the assets that the game ships with.
Mods are packages that share the directory structure of the base, but change some files in it.

Each section of this guide describes how to create a specific type of mod.

Enjoy personalizing your Unity of Command II experience!

Unity of Command II uses YAML configuration files for almost everything.
These files define things like the camera, AI behavior, game rules and much more!
Most of them can be found in the base package at _packages/base/config.

Let's create a new camera mod! First, create a new package in AppData _packages. I'm calling mine camera_mod.


Now, create constants.patch.yml in the camera_mod folder with the same directory structure as in the base package.


constants.yml contains a lot of data, but we can modify only some of it.
For example in the camera mod, I've only edited some of the zoom values.
The camera mod we've crated allows for some pretty epic zoom outs!


To create a localization mod, follow these steps:

• Create a new package
  
• In the package directory, create localization/{language_code}/strings.yml
  
• language_code should be from the ISO 639-2 standard[en.wikipedia.org]
  
• The original texts can be found in the Steam installation folder {path_to_steam}\steamapps\common\Unity of Command 2\_packages\base\localization\eng
  
• Copy-paste the data from a yaml file into strings.yml and translate the text

To upload the mod, run the steam_ws_upload command with the prep script in the game's install directory.


The {package_name} is the name of the mod's package directory. So it would be camera_mod for the above example.
The --visibility kwarg can be 0 (public), 1 (friends only) or 2 (private).
Adding a thumb.jpg to the mod's package directory will set it as the mod's thumbnail.
When updating the mod the --title, --description and --visibility kwargs aren't required.

Happy modding!

The list of moddable 3D assets can be found in _packages\base\assets\models.
Here I'll be using us_inf_42_mesh.npz (US infantry model) to explain the process, but any other can be used.

In the game's Steam directory, create assets_in/unit_models.
In assets_in/unit_models, create a directory with the name of the model your mod will replace.
Model name is everything before the _mesh.npz suffix. E.g. in case of us_inf_42_mesh.npz, the model name is us_inf_42.

In assets_in/unit_models/us_inf_42 create a .yml with the same name as the model.

us_inf_42.yml:

Let's explain each section of the yml:

• materials - material specification tag
  
  • map_Kd - name of the diffuse map that's located in the same directory as the .yml. No alpha channel.
    
  • map_Ks - name of the specular map that's located in the same directory as the .yml. Grayscale.
    
  • map_bump - name of the normal map that's located in the same directory as the .yml. No alpha channel.
    
  • shininess - shininess factor
    
  • Kd - diffuse factor
    
  • Ks - specular factor
• mesh_file - name of the mesh file that's located in the same directory as the .yml. Can be .obj or .fbx
  
• properties - mesh properties
  
  • scale - mesh scale
    
  • offset - object space mesh offset
• variations - mesh variations
  
  • shooting - name of the mesh file that's located in the same directory as the .yml. Shooting pose for infantry units. Not needed for non infantry units. Can be .obj or .fbx

Once the .yml has been setup, run the following command to build it into the .npz file that the game can understand: