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This article is geared toward novice modders who are just learning how to create mods for Mass Effect. Generally, the content below applies to Mass Effect 2 and Mass Effect 3, as they share similar game structure. Other than that caveat, modders for game assets of all varieties—texture, mesh, coalesced, and content—should find everything you need to get started turning your idea into a mod.

Preparation + Research

Formulating ideas is easy. Executing them is not.

Modding the Mass Effect trilogy has a significant learning curve. You'll need patience and persistence. These are not easy games to mod.

The first thing to do upon deciding you want to create a mod for Mass Effect is to start orienting yourself to the game. You'll need some basic knowledge about how the game works before you delve into editing files or creating textures.

This basic knowledge should include aspects such as:

  • How does the game organize its content?
  • Where is the content located that I want to mod?
  • What types of mod formats are available?
  • What are the current "best modding practices"?
  • What file formats will the game recognize for textures?
  • Does installation order matter for Mass Effect mods?

This article will provide guidance on many of these questions. In addition, all mod creators should start by reading (at minimum) these articles:


Another thing you'll need to consider before embarking on your mod, is whether or not it will be your unique work or built on someone else's content. If the former, then this section is likely moot and you can move on. If the latter, then you should proceed with this section on Permissions.

Over the past ten years, modding has continued to grow in popularity as a hobby. As a result, dealing with the aspect of permissions has become more and more complicated. Many folks are either ignorant of the legal ramifications of using someone else's creative work, have philosophical objections as to whether permissions should be needed, or simply don't care. This section deals with how to properly ask for permissions from other mod authors when you wish to use their assets. (Later on we'll go into how to properly compose permissions for your mod.)

Tip Mods are unique creative works like music and books. In the U.S. and many other jurisdictions, they are automatically copyrighted upon creation; no legal action on part of the creator is required. This copyright lasts for the life of the author +70 years. When you fail to ask permission to use another mod's assets, you are not only treating that author with disrespect, you are violating the law.

Always keep the following details below in mind when making a mod. This is the standard used by Nexusmods and many other mod-hosting sites:

  1. If your mod will be built upon anyone else's assets you must have permission from the author.
  2. If you will be patching into someone else's mod—at all—you must have permission from the author.
  3. You cannot override another mod's unique content with your own without prior permission from the author. For example, mod "K" adds feature "L" to to the game. You cannot come along later and modify feature "L" without prior permission.
  4. It is not "good enough" to simply acknowledge a mod/modder in the credits upon release. You must obtain permission PRIOR to release.
  5. Unless specified by the author permissions are always on a per mod and per asset basis. In other words, the author gives you permission to use their asset "X" in your mod "Y". If you want to use their asset "X" in mod your new mod, "Z", you need new permission. If you find another asset of theirs, "W", and you want to use it in your mods "Y" and "Z", you need new permission.

Finally, don't ask for permission after you've started development on your mod, in an attempt to manipulate/guilt the other modder into allowing use of their assets. Be a mature human and ask before you start.

Tip Treat modders with respect. If you are successful in your endeavor, the shoe will soon be on the other foot and you'll appreciate the consideration.

Regardless of the outcome of your permission request, recognize that mod authors are not obligated to share use of their assets. If they allow it, show appreciation. If they do not, thank them for their time and move on.


Compatibility is the sticky wicket of every mod. Even if you become involved in a modding community that is initially small, that community will inevitably grow and issues with compatibility will become more frequent. In some very large modding communities—Skyrim, for example—it's literally impossible to ensure compatibility across all mods.

Determining Compatibility

Mods vary widely when it comes to compatibility. The compatibility of any two mods is affected by a number of things;

  • The format in which the mod is distributed
  • The files contained in the mod
  • The exact content modded in those files

How do you know if your mod is incompatible with another mod out there? You have to look.Ultimately, if your mod alters the same files (or the same content), they are incompatible.

Tip Using visual evidence in game as a measure of two mods compatibility is only as reliable as your knowledge of the content in both mods. In other words, if you don't have intimate and detailed knowledge of how the other mod works, you might not realize it's not functioning properly. Compatibility cannot be "eyeballed".

If you know of existing mods that are widely-used and that will be incompatible with the mod you're thinking about creating, it's good to know that before you get started. Why? Because then you can plan for it. You can even choose a format that will limit or omit compatibility problems.

Should you Create Compatibility?

As a mod author, it's your decision whether or not to create compatibility between your mod and other mods. You are under no circumstances obligated to create compatibility, though your users will complain if you exercise your right not favor their other mods with a patch.

When deciding whether to create compatibility, you may want to consider these questions:

  • Do you want to spend the time and effort to create compatibility?
  • Do you use the other mod, allowing you to easily test your patch?
  • Are you willing to support compatibility for as long as you provide support for your mod?
  • Have you acquired permission from the author to create the patch?

Some mods are inherently compatible and cannot be patched. For example, two texture mods that modify the same game texture, or two content mods that both alter the ME3 ending. Mods of this nature are innately incompatible and cannot be patched.

If you do decide to create compatibility, the exact method of doing so varies with your mod's format and the content that's incompatible. We'll talk more about that in the next few sections.

Choosing a Format

The format you pick to distribute your mod is one of the most important decisions you'll make during development. This is because it not only affects your content and how you create the mod, but how your users install the mod, and compatibility issues that will arise with other mods.

Best Modding Practices

Any existing modding community will already have standards in place as to how different types of mods are distributed. As a new modder, you should try to adhere to these "best practices" as much as possible. If you don't, then you better be ready to justify your reason, as departing from those practices has the potential to create headaches for other modders (not to mention yourself and your users).

When it comes to the Mass Effect trilogy, start learning about formats and best practices by reading the Mod Formats article on this wiki. It summarizes all file types in the trilogy and all mod formats usable with ME3Explorer. From there, consider the information below which supplements the content in the Mod Formats article, strictly from a modder's perspective.

Texture TPF/DDS file
Mesh MOD file
Coalesced DLC mod
Content mod (small, simple) MOD file or Loose PCC
Content mod (medium, complex) DLC mod

Texture Mods

Texture mods contain textures, only. Distribution is almost always best via TPF/DDS, but there are some exceptions. TPFs are more convenient for users, as they can be used with both TPF Tools and Texmod. In addition, the DDSes bundled in the TPF can be extracted and installed via Texplorer.

  • Standard Textures (with mipmaps) — This includes clothing, armor, weapons, and the like. Distribution as TPF or raw DDSes is always best option. This will avoid almost any compatibility issue and will allow your users to install the textures into other mods.
  • GUI textures (no mipmaps) — It's unlikely anyone would want to distribute a mod strictly of GUI textures. However, if so, TPF/DDSes do the job, but only if installing into an existing PCC (GUI textures are PCC-stored). If you build your own custom-named PCC files, then the mod would need to be distributed as a DLC mod.

Please note that texture mods should never be distributed as DLC mods. Doing so is completely unnecessary and will create a nightmare of compatibility issues with other mods.

Mesh Mods

Mesh mods contain new or alternate meshes for existing game assets. Frequently, they are also accompanied by textures that should be released as outlined above. Distribution of mesh mods themselves varies with the type of file being modified and whether the mesh is an edited or new game object:

  • BIOG/BIOH Files — MOD files, created and installed with ModMaker are almost always the best option for edited meshes in BIOG/H files. Loose PCCs and DLC mods will result in more compatibility issues. Be aware that both BIOG and BIOH files are very commonly modded and will be affected by other mods.
  • BIOD/BIOP Files — Edited meshes that affect these files must be handled with extreme care, as they contain core game plot and story content. MOD files should be used when at all possible, in order to retain compatibility with other mods. This ease of compatibility is what ModMaker was designed for.
  • New Files or New MeshesNew meshes (made via cloning) and new files can only be implemented via full PCC replacement, either via loose files or a DLC mod. This is regardless of file type.

Coalesced Mods

Coalesced mods alter the various "coalesced" files in the base game or DLC. These types of mods should be distributed as DLC mods, when the content allows (not all coalesced content will work in DLC mod form). This will allow you to insert content for your mod, specifically, rather than overwriting the user's files directly.

There are also other modding tools available for ME3 that provide additional options for coalesced modding.

Content Mods

Content mods alter gameplay and story content stored in BIOD and BIOP files. These mods are the most apt to have compatibility issues with other mods due to their size and scope. Due to this, distribution of content mods varies with both size and types of files modified:

  • Small, PCC-only edits — If the mod is extremely small and only alters an export or two in a couple PCCs, then a MOD file is a good choice. MOD files can be made to install into the base game or DLC files, and therefore are innately compatible with whatever they install into. Another option for smaller mods is distribution of loose PCC files. Users can dump them into the base Cooked, autotoc, and they're ready to go. Very simple.
  • Medium+, non-PCC edits — If the mod edits several PCCs in a way that is incompatible with ModMaker's current capabilities, then a DLC mod is necessary. A DLC mod is also required when editing or adding content to the TLK, CND, Startup, or coalesced files. BioWare's versions of these files should not be distributed in mods, as they are too prone to conflict.

A Special Word on the DLC Mod Format

The DLC mod method was first published by JohnP on the ME3Explorer forum in May 2014. Since then, it has been wholeheartedly embraced and advocated by the community as the best way to distribute mods.

That said, it's important for all new modders to realize this perspective is highly-dependent on the toolset community's focus on content modding. DLC mods are what make advanced content modding possible. Without DLC mods, content mod distribution becomes a nightmare. This is because most content mods need to modify or add content to core game files like TLKs, CNDs, Startups, and coalesceds. This has the effect of almost all content mods inherently conflicting with each other unless they are distributed as DLC mods. To make matters worse, ModMaker cannot apply changes to any of these four file types, which makes distribution via MOD file out of the question.

Another detail to keep in mind is there cannot have an infinite number of DLC mods. Each must contain a mount priority integer and no integer can be reused. Priority for each mod must be considered in the context of other available mods, and there are only a limited number of "slots" available between any two mods. This means that with every new DLC mod compatibility for the community as a whole gets more difficult.

This is why DLC mods should be used only when absolutely necessary. Despite their convenience they are not the best solution for every type of mod. Ultimately, the decision is yours and yours alone. However, the community will appreciate you distributing your mod in a format that allows for maximum compatibility—and doesn't unnecessarily prioritize your work over the work of others.

Creating the Mod

Texture and Mesh Mods

Coalesced Mods

Content Mods


Asking for Help

Packaging the Mod

DLC Mods + Mount Priority

Compatibility Patches

Licensing + Legal

Open vs Closed


Compatibility Patches

Choosing a Host

Modder's Etiquette

The DLC Mod Compatibility Resource

Providing Support

Paragon250 This article was created by Giftfish, with input and feedback from the ME3Explorer and Nexusmods communities.