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Last Updated: 2026-04-09

Assembly (C#) Mod

This type of mod creates compiled binaries/dll without code written in C#/.NET. The benefits of this workflow and mod type compared to a Lua mod are:

  • Complete access to all Barotrauma functions.
  • Better performance.
  • Much faster loading for players.
  • Custom game objects (ie. ItemComponents).
  • Smart autocomplete and documentation.
  • Hot Reload/Edit-and-Continue (edit code while it's running).
  • Strong error checking and live debugging support.

The cons are:

  • Players must have C# mods enabled.
  • More complex language.
  • The project requires more setup.
  • Mods may need to be recompiled every few updates (9-12 months) if there are major game changes.

Getting Started

1. IDE Setup

You will need an IDE that supports .NET 8 as a platform/SDK target. The following IDEs have been tested with the project and should work out of the box:

You may use another IDE but it will be up to you to fix any issues arising from it.

Git is the industry standard for version control and is completely free. It allows you to save your work, revert back to previous versions, collaborate with others and more. It is not required but very helpful. Download it here and install it.

We will be using Git in the installation going forward.

3. Create the Project

  • Create/Log in to your Github account and then go to LuaCsModTemplate.
  • In the top-right corner, click Use this Template.
  • Select Create New Repository.
  • Name the repository the name of your mod.

    github-use-template-1191x628.png

4. Clone/Create Local Mod Copy

  • In your new github repo, select the green <> Code button and copy the HTTPS repo link.

    github-clone-link-450x364.png

  • Go to the directory on your PC where you want to store the project.
  • Open Git Bash or CMD in that folder/directory (Google how to for your platform).
  • Note: On Windows, you can right-click in the folder and select Open Git Bash here.
  • in the terminal type: git clone <paste your repo link here> and press enter.
  • Note: For Git Bash, the paste command is Shift+Insert. Don't ask me who decided this, I want to find them too.
  • When completed, verify that the folder contents at least contain what you see on your Github repo.

5. Setup the Project

  • Download the Luatrauma reference dlls zip file and extract the contents into the /Refs/ folder in your project.
  • Note: Make sure that the files are in the top-level directory of /Refs/ and not nested inside an additional folder from the extraction.
  • Open Build.props in the main directory and go to the User/Mod Settings section.
  • Replace contents of the ModDeployDir element with the path to your Barotrauma local mods, ie. <BarotraumaGame>/LocalMods/<YourModName>/:
    • Note: ModDeployDir must end with a '\'
    • Example: "C:\Program Files (x86)\Steam\steamapps\common\Barotrauma\LocalMods\MyModName\"

  • Replace the contents of AssemblyName and RootNamespace with your mod's name using the following rules:

    • No spaces.
    • No special characters (ie. < >, \ / ;). Periods (.) are allowed.
    • Use English characters only.
    • Must start with a letter.

      build-props-1245x886.png

  • Copy the AssemblyName and then open Assets/Content/ModConfig.xml.

  • Replace [MODASSEMBLYNAME] with your AssemblyName (keep the .dll ending).

    Tip: Use your IDE, Notepad++ or another editor's 'Find and Replace' function to quickly do this.

  • Open Assets/Content/filelist.xml and change the mod name to your mod's name.


mod-config-modassemblyname-1033x408.png
- In the main directory, rename MyModName.sln to your mod's name.

6. Test the Project.

  • Open the renamed <MyModName.sln>.
  • Build the project.
  • In the top bar, select the Startup Project, then Launch Option / Configuration for your system (ie. WindowsClient: Launch Barotrauma ).
  • Launch Barotrauma.

    Visual Studio:

    startup-profile-select-vs-442x266.png

Jetbrains Rider:

startup-profile-select-rider-860x326.png

  • On the Main Menu, add your mod to the Enabled Packages/Mods list.
  • Go into the Sub Editor and open the console (F3).
  • Check to see if your mod was loaded in the console.

    mod-plugin-running-subeditor-979x509.png

If your mod loaded successfully, you are now ready to mod!

Project Structure and Where to Code

Your entry point/startup for your code is SharedProject/SharedSource/Plugin.cs.

All of your mod's non-code content should be put in ./Assets/Content/.
All of your Client-only code should be in ClientProject/ClientSource.
All of your Shared code should be in SharedProject/SharedSource.
All of your Server-only code should be in ServerProject/ServerSource.

Vanilla files should be added to Assets/Content/filelist.xml as per normal XML modding. Modded LuaCs-specific files is added via Assets/Content/ModConfig.xml.

For more details on ModConfig.xml and the LuaCs API, see the API pages.