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Modding Unity-based games

Before proceeding

This guide applies to games made in the Unity engine, such as maimai DX, O.N.G.E.K.I. and Card Maker.

It is highly recommended to use an unpatched Assembly DLL as your base!

Patches have historically been hardcoded into the unprotected Assembly-CSharp.dll

The modern approach is to use BepInEx to load custom patches without tampering with Assembly-CSharp.
BepInEx can be used to load all mods, including those made for MelonLoader and MonoMod

Installing BepInEx

Some maimai DX mods are only compatible with BepInEx 5.4.22

  • Extract the BepInEx folder to the App\package folder (ignore other files such as .doorstop_version)

  • Modify segatools.ini with the following:

[unity]
enable=1
targetAssembly=BepInEx\core\BepInEx.Preloader.dll

Installing mods

BepInEx plugins

Place them in BepInEx\plugins.

Melonloader mods and plugins

  • Download MLLoader-UnityMono-BepInEx5 of the latest BepInEx.MelonLoader.Loader.
  • Extract it into App\package.
  • Place mods in MLLoader\Mods.

MonoMod patches

These patches always follow the naming pattern: Assembly-CSharp.Name.mm.dll.