Unreal Engine 4/5 Scripting System

Lua scripting system platform, C++ Modding API, SDK generator, blueprint mod loader, live property editor and other dumping utilities for UE4/5 games.

Major features

Lua Scripting API: Write lua mods based on the UE object system
Blueprint Modloading: Spawn blueprint mods automatically without editing/replacing game files
C++ Modding API: Write C++ mods based on the UE object system
Live Property Viewer and Editor: Search, view, edit & watch the properties of every loaded object, great for debugging mods or figuring out how values are changed during runtime
UHT Dumper: Generate Unreal Header Tool compatible C++ headers for creating a mirror .uproject for your game
C++ Header Dumper: Generate standard C++ headers from reflected classes and blueprints, with offsets
Universal UE Mods: Unlock the game console and other universal mods
Dumpers for File Parsing: Generate .usmap mapping files for unversioned properties
UMAP Recreation Dumper: Dump all loaded actors to file to generate .umaps in-editor
Other Features, including Experimental features at times

Targeting UE Versions: From 4.12 To 5.3

The goal of UE4SS is not to be a plug-n-play solution that always works with every game. The goal is to have an underlying system that works for most games. You may need to update AOBs on your own, and there's a guide for that below.

Basic Installation

The easiest installation is via downloading the non-dev version of the latest non-experimental build from Releases and extracting the zip content to /{Gameroot}/GameName/Binaries/Win64/.

If your game is in the custom config list, extract the contents from the relevant folder to Win64 as well.

If you are planning on doing mod development using UE4SS, you can do the same as above but download the zDEV version instead.

Links

Full installation guide

Fixing compatibility problems

Lua API - Overview

Generating UHT compatible headers

Custom Game Configs

Creating Compatible Blueprint Mods

UE4SS Discord Server Invite

Unreal Engine Modding Discord Server Invite

Build requirements

A computer running Windows.
- Linux support might happen at some point but not soon.
A version of MSVC that supports C++23:
- MSVC toolset version >= 14.39.0
- MSVC version >= 19.39.0
- Visual Studio version >= 17.9
- More compilers will hopefully be supported in the future.
Rust toolchain >= 1.73.0
xmake >= 2.9.3

Build instructions

Clone the repo.
Execute this command: git submodule update --init --recursive Make sure your Github account is linked to your Epic Games account for UE source access. Do not use the --remote option because that will force third-party dependencies to update to the latest commit, and that can break things. You will need your github account to be linked to an Epic games account to pull the Unreal pseudo code submodule.

There are several different ways you can build UE4SS.

Building from cli

Configuration settings

xmake allows you to flexibly configure some build options to suit your specific needs. The following is a non-comprehensive list of configuration settings you might find useful.

Important

All configuration changes are made by using the xmake config command. You can also use xmake f as an alias for config.

After configuring xmake with any of the following options, you can build the project with xmake or xmake build.

Mode

The build modes are structured as follows: <Target>__<Config>__<Platform>

Currently supported options for these are:

Target
- Game - for regular games
- CasePreserving - for games built with case preserving enabled
Config
- Dev - development build
- Debug - debug build
- Shipping - shipping(release) build
- Test - build for tests
Platform
- Win64 - 64-bit windows

Tip

Configure the project using this command: xmake f -m "<BuildMode>". -m is an alias for --mode=<BuildMode>.

Patternsleuth (Experimental)

By default, the patternsleuth tool installs itself as an xmake package. If you do not intend on modifying the patternsleuth source code, then you don't have to configure anything special. If you want to be able to modify the patternsleuth source code, you have to supply the --patternsleuth=local option to xmake config in order to recompile patternsleuth as part of the UE4SS build.

Proxy Path

By default, UE4SS generates a proxy based on C:\Windows\System32\dwmapi.dll. If you want to change this for any reason, you can supply the --ue4ssProxyPath=<path proxy dll> to the xmake config command..

Profiler Flavor

By default, UE4SS uses Tracy for profiling. You can pass --profilerFlavor=<profiler> to the xmake config command to set the profiler flavor. The currently supported flavors are Tracy, Superluminal, and None.

Version Check

By default, xmake will check if you have the minimum required version of Rust or MSVC installed (if you are using the MSVC toolchain). If you do not, it will throw an error on the configure step. If you want to ignore this check, you can pass --versionCheck=n to the xmake config command.

Once you set the flag, the option value be set until you specify otherwise.

Therefore, to not check versions when running xmake project -k vsxmake2022, you must first run the xmake config --versionCheck=n command, then run the xmake project -k vsxmake2022 command.

Helpful `xmake` commands

You may encounter use for the some of the more advanced xmake commands. A non-comprehensive list of some useful commands is included below.

Syntax	Aliases	Uses
`xmake <command> --yes`	`xmake <command> -y`	Automatically confirm any user prompts.
`xmake --verbose <command>`	`xmake -v <command>`	Enable verbose level logging.
`xmake --Diagnostic <command>`	`xmake -D <command>`	Enable diagnostic level logging.
`xmake --verbose --Diagnostic --yes <command>`	`xmake -vDy <command>`	You can combine most flags into a single `-flagCombo`.
`xmake config`	`xmake f`	Configure xmake with any of these options.
`xmake clean --all`	`xmake c --all`	Cleans binaries and intermediate output of all targets.
`xmake clean <target>`	`xmake c <target>`	Cleans binaries and intermediates of a specific target.
`xmake build`	`xmake b`	Incrementally builds UE4SS using input file detection.
`xmake build --rebuild`	`xmake b -r`	Forces a full rebuild of UE4SS.
`xmake build <target>`	`xmake b <target>`	Incrementally builds a specific target.
`xmake show`		Shows xmake info and current project info.
`xmake show --target=<target>`	`xmake show -t <target>`	Prints lots of information about a target. Useful for debugging scripts, compiler flags, dependency tree, etc.
`xmake require --clean`	`xmake q -c`	Clears all package caches and uninstalls all not-referenced packages.
`xmake require --force`	`xmake q -f`	Force re-installs all dependency packages.
`xmake require --list`	`xmake q -l`	Lists all packages that are needed for the project.
`xmake project --kind=vsxmake2022 --modes="Game__Shipping__Win64"`	`xmake project -k vsxmake2022 -m "Game__Shipping__Win64"`	Generates a Visual Studio project based on your current `xmake config`uration. You can specify multiple modes to generate by supplying `-m "Comma,Separated,Modes"`. If you do not supply any modes, the VS project will generate all permutations of modes.

Opening in an IDE

Visual Studio / Rider

To generate Visual Studio project files, run the xmake project -k vsxmake2022 -m "Game__Shipping__Win64" command.

Afterwards open the generated .sln file inside of the vsxmake2022 directory

Note that you should also commit & push the submodules that you've updated if the reason why you updated was not because someone else pushed an update, and you're just catching up to it.

Warning

The vs. build plugin performs the compile operation by directly calling the xmake command under vs, and also supports intellisense and definition jumps, as well as breakpoint debugging. This means that modifying the project properties within Visual Studio will not affect which flags are passed to the build when VS executes xmake. XMake provides some configurable project settings which can be found in VS under the Project Properties -> Configuration Properties -> Xmake menu.

Caution

If you have multiple Visual Studio versions installed, run xmake f --vs=2022, otherwise you may encounter issues with the project generation.

Configuring additional modes

Tip

Additional modes can be generated by running xmake project -k vsxmake2022 -m "Game__Shipping__Win64,Game__Debug__Win64". Further explanation can be found in the xmake command table.

Regenerating solution best practices