UELib

April 19, 2026 · View on GitHub

Nuget Platform License

UELib

The Unreal library (UELib) provides you an API to read (parse/deserialize) contents of Unreal Engine game package files, such as .UDK and .UPK files.

The main goal of UELib is to decompile the UnrealScript byte-code, which is achieved by reconstructing the original UnrealScript source from Unreal data classes:

UObject, UField, UConst, UEnum, UProperty, UStruct, UFunction, UState, UClass,
UTextBuffer, UMetaData, UPackage

UELib is also capable of deserializing other Unreal data classes:

UFont, USound, UPalette, UTexture,
UTexture2D, UTexture2DDynamic, UTexture2DComposite, UTexture3D,
UTextureCube, UTextureFlipBook, UTextureMovie
UPrimitive, UPolys,
UComponent

Install

    Install-Package Eliot.UELib
ModuleVersionLicense
NugetGitHub
    using UELib;

    // Instantiates a FileStream and deserializes the package's header, will also auto-detected a suitable build to associate the package with.
    var package = UnrealLoader.LoadPackage(@"C:\Path\Package.upk", System.IO.FileAccess.Read);
    Console.WriteLine($"Version: {package.Summary.Version}");

    // Necessary if working with packages that have been cooked for a console platform, and IF the build was not properly auto-detected.
    // package.CookerPlatform = BuildPlatform.Console;

    // Initializes the registered classes, constructs and deserializes(loads) the package objects.
    package.InitializePackage();

    // Now we can iterate over all the initialized objects, but beware! This includes fake-import objects.
    foreach (var obj in package.Objects)
    {
        // If positive then we have an export, or import if negative, if null, we are working with a 'None' object, but this shouldn't occur here.
        if ((int)obj > 0)
        {
            Console.WriteLine($"Export:");
        }
        else if ((int)obj < 0)
        {
            Console.WriteLine($"Import:");
        }

        Console.WriteLine($"ObjectIndex: {(int)obj}");
        Console.WriteLine($"Name: {obj.Name}");
        Console.WriteLine($"Class: {obj.Class?.Name}");
        Console.WriteLine($"Outer: {obj.Outer}");
        Console.WriteLine($"Path: {obj.GetReferencePath()}");
    }

If you're looking to modify the library for the sole purpose of modding UE Explorer consider forking UE Explorer instead (UELib is linked as a sub-module)

Compatible Games

UELib supports these kinds of content, but may vary from game to game:

  • Script
  • Audio
  • Texture (No .tfc support)
  • Model
  • Animation

Important

Audio and Textures are expected to work for most games, but has not been confirmed.

NameEnginePackageStateScriptAudioTexture
Unreal Engine 1✅✅✅
Unreal100-22661/000✅✅✅
Hired Guns21661/000✅✅✅
Star Trek: The Next Generation: Klingon Honor Guard21961/000✅✅✅
X-COM: Alliance200-22061/000Bad output at the start of functions (BeginFunctionToken)✅✅✅
Dr. Brain: Action Reaction22463-68/000✅✅✅
Nerf Arena Blast22563-68/000✅
The Wheel of Time225:WoT63-68/000✅✅✅
Unreal Mission Pack: Return to Na Pali226b68/000✅✅✅
Unreal Tournament338-43668-69/000✅✅✅
Deus Ex400-43668/000✅
Jazz Jackrabbit 3D40068/000✅✅✅
Duke Nukem Forever (2001)61368/002UStruct offsets are off leading to bad output code✅
Rune40069/000✅
Unrealty40569/000✅
Adventure Pinball: Forgotten Island42069/000✅✅✅
X-COM: Enforcer42069/000✅✅✅
Tactical Ops: Assault on Terror43669/000✅
Star Trek: Deep Space Nine: The Fallen33873/000✅
Harry Potter and the Sorcerer's Stone43676/000✅
Harry Potter and the Chamber of Secrets43379/000✅
Disney's Brother Bear43380/000Link✅
Mobile Forces43681-83/000, 69✅
Clive Barker's Undying42072-85/000Versions 72 to 83 are not auto detected.✅✅✅
Deus Ex: Invisible War777:Flesh95/069Thanks in part to @hanfling; LinkedData not supported✅
Thief: Deadly Shadows777:Flesh95/133Thanks in part to @hanfling; LinkedData not supported✅❌
Unreal Engine 2✅✅✅
XIII829100/058✅
Tom Clancy's Splinter Cell829100/017✅
Tom Clancy's Splinter Cell: Pandora Tomorrow829102/028:SCXPC offline version✅
Tom Clancy's Splinter Cell: Chaos Theory829100/120:SCX, 175/000:ShadowStrike(PS3) version and (PC) demo version, , Versus mode not supported✅✅
Tom Clancy's Splinter Cell: Double Agent829100/167:SCX, 275/000:ShadowStrike(PC) Offline mode version, Online mode not supported✅
Tom Clancy's Splinter Cell: Blacklist829102/116:LEADIn part thanks to @shryder. Third-party decompression is required✅
Tom Clancy's Rainbow Six 3: Raven Shield600-927118/012-014✅✅
Magic: The Gathering - Battlegrounds926118/000✅✅✅
Postal 2: Paradise Lost1417118/002✅
Unreal Tournament 20031077-2225119/025✅✅✅
Devastation600-?118-120/004-008✅✅✅
Dead Man's Hand2110123/002✅✅✅
Unreal II: The Awakening829-2001126/2609✅
Unreal II: eXpanded MultiPlayer2226126/000Custom features are not decompiled✅
Desert Thunder2226126/000✅
Marine Heavy Gunner: Vietnam2226126/000✅✅✅
Land of the Dead: Road to Fiddler's Green2226126/001✅✅✅
Netherworld: Beyond Time I Stand2226127/002Bad property deserialization✅✅✅
Unreal Tournament 20043120-3369128/029✅✅✅
Red Orchestra: Ostfront 41-453323-3369128/029✅✅
Killing Floor3369128/029✅✅
D.M.Z.: North Korea3369128/029✅✅✅
Close Quarters Conflict3369128/029✅✅✅
Outlaw Chopper3369128/029✅✅✅
Marine Sharpshooter 33369128/029✅✅✅
Marine Sharpshooter 4: Locked and Loaded3369128/029✅✅✅
Mission Biotech3369128/029✅✅✅
America's Army 23339128/032:0332.5, 2.6, 2.8✅
America's Army (Arcade)3339128/0322.6✅
Harry Potter and the Prisoner of Azkaban2226129/000Link✅
Shrek 22226129/000✅
Shark Tale2226129/003✅
Lemony Snicket's A Series of Unfortunate Events2226129/003✅
Combat: Task Force 1212110129/010✅✅✅
Shadow Ops: Red Mercury2110129/010✅✅✅
World War II Combat: Road to Berlin2110129/010✅✅✅
World War II Combat: Iwo Jima2110129/010✅✅✅
Swat 42226:Vengeance129/027✅
Vanguard: Saga of Heroes2226129/035✅
Stargate SG1: The Alliance4180130/004✅
Tribes: Vengeance2226:Vengeance130/027✅
Bioshock2226:Vengeance130-141/056✅
Arctic Combat3369134/038-039Thanks to @EDITzDev. Third-party decompression is required✅✅✅
Star Wars: Republic Commando2226134-159/001✅
The Regiment2226136/000✅✅✅
Men of Valor926137/000PC✅
Bioshock 22226:Vengeance143/059✅
Advent Rising2226143-146/007✅✅✅
Unreal Championship 2: Liandri Conflict3323151/002Third-party✅
Duke Nukem Forever (2011)Originally UE1 and upgraded to UE2&3156/036Extraction is required✅❌✅
Unreal Engine 3✅✅✅
RoboHordesUnknown198-200/000✅✅✅
Tom Clancy's Rainbow Six: VegasUnknown241/066✅
Tom Clancy's Rainbow Six: Vegas 2Unknown241/071✅
Tom Clancy's EndWarUnknown329/000✅
Roboblitz2306369/006✅✅✅
Stranglehold2605375/025✅
Mass Effect (Xbox 360)2674391/092Xenon✅
Warmonger: Operation Downtown Destruction2859419/003✅
Medal of Honor: Airborne2859421/011✅✅
Frontlines: Fuel of War2917433/052✅
Army of Two3004445/079Overall quality has not been verified✅
Mortal Kombat Komplete Edition2605472/046✅
Stargate Worlds3004486/007✅
Gears of War3329490/009✅
Mass Effect (Windows)3240491/1008(~112)PC✅
Huxley3240496/016-023Contributed by @EDITzDev✅✅
Robert Ludlum's The Bourne Conspiracy511/039✅
Transformers: War for Cybertron511/144,145PC, PS3, Xenon✅
Unreal Tournament 33809512/000✅
Mirrors Edge3716536/043✅
Alpha Protocol3857539/091✅
APB: All Points Bulletin3908547/028-032✅
X-Men Origins: Wolverine4206568/101Overall quality has not been verified✅
Gears of War 24638575/000✅
CrimeCraft4701576/005✅
Batman: Arkham Asylum4701576/21Contributed by @etkramer✅
Medal of Honor (2010)100075???581/058Bad byte-codes✅❌
Saw4869584/003✅✅✅
Singularity4869584/126✅
MoonBase Alpha4947587/000✅
The Exiled Realm of Arborea or TERA4206610/014✅
Monday Night Combat5697638/000✅
DC Universe Online5859638/6405Contributed by @theFoof✅
Unreal Development Kit5860-12791664-868✅✅✅
Blacklight: Tango Down6165673/002✅✅
Saw II: Flesh & Blood6165673/004Unsupported, but loadable❌❌❌
Dungeons & Dragons: Daggerdale6165674/000✅
Dungeon Defenders6262678/002✅✅
Mass Effect 3 (Windows)6383684/194PC (platform must be set to Console)✅
Mass Effect: Legendary Edition (Windows)6383684/171PC (platform must be set to Console)✅
Alice Madness Returns6760690/000✅
The Ball6699706/000✅
Game of Thrones6829727/000✅
Bioshock Infinite6829727/075✅
Bulletstorm7052742/029✅
Red Orchestra 2: Heroes of Stalingrad7258765/Unknown✅
Rising Storm 2: Vietnam7258765/771✅
Aliens: Colonial Marines7422787/047✅✅
Infinity Blade 17595788/001Console✅
Dishonored9099801/030✅
Tribes: Ascend7748805/Unknown✅
Tony Hawk's Pro Skater HD✅
Rock of Ages7748805/000✅
Batman: Arkham City7748805/101✅
Batman: Arkham Origins7748807/138Not verified✅
Sanctum7876810/000✅
AntiChamber7977812/000✅
Waves8171813/000✅
Super Monday Night Combat8364820/000✅
Gears of War 38653828/000✅
Quantum Conundrum8623832/32870✅
Borderlands4871Unknown✅
Borderlands 28623/0023832/056✅
Borderlands: Game of the Year Enhanced5001/0001832/058✅
Remember Me8623832/021✅
Gears of War: Ultimate Edition3340835/056Actual package version is 490; thanks to @PaoloTK✅
Gears of War: Reloaded3340835/076Actual package version is 490; thanks to @PaoloTK✅
The Haunted: Hells Reach8788841/000✅
Asura's Wrath8788841/000-zlib; platform needs to be set to console.✅
Blacklight Retribution8788-10499841-864/002✅✅
Infinity Blade 29059842-864/001Console✅
Q.U.B.E8916845/000✅
DmC: Devil May Cry8916845/004✅
XCOM: Enemy Unknown8916845/059✅
XCOM 2: War of the Chosen8916845/120Contributed by @robojumper✅
Gears of War: Judgement10566846/000✅
Transformers: Fall of Cybertron846(~587)/181✅
Deadpool846(~587)/181✅
InMomentum8980848/000✅
Unmechanical9249852/000✅
Star Wars: First Assault9249852/008Xbox360; platform needs to be set to console✅❔✅
Deadlight9375854/000✅
Land of the Dead9375854/000✅
Borderlands Legends9505859/000iOS; platform needs to be set to console✅
Ravaged9641859/000✅
The Five Cores9656859/000✅
Painkiller HD9953860/000✅
Chivalry: Medieval Warfare10246860/000✅
Hawken10681860/004✅
Styx: Master of Shadows10499860/004✅
Abyss Odyssey10246861/000✅✅✅
Batman: Arkham Knight863/32995Not verified✅
Rocket League10897867/009 (868/032 has not been tested)Decryption required✅
Gigantic: Rampage Edition19100867/010Contributed by @HyenaCoding✅
Infinity Blade 3868/000Console✅
Guilty Gear Xrd10246868/003Decryption required✅
Outlast12046868/003✅
Might & Magic Heroes VII12161868/004(Signature and custom features are not supported)✅
Bombshell11767870/000✅
Orcs Must Die! Unchained20430870/000✅
Sudden Attack 210897870/108-109✅✅✅
Gal*Gun: Double Peace10897871/000✅
Battleborn8623/1055874/078✅
A Hat in Time12097877-893/005Contributed by @Un-Drew✅
Bulletstorm: Full Clip Edition12212877/041✅
Blue Estate The Game10246893/000✅
Shadow Complex Remastered10897893/001✅
Borderlands 2 VR8637/0029895/046✅
Soldier Front 26712904/009✅
Rise of the Triad10508Unknown✅
Sherlock Holmes: Crimes and Punishments10897Unknown✅
Alien Rage7255Unknown✅

Beware, opening an unsupported package could crash your system! Make sure you have saved everything before opening any file!

Note UE3 production-ready packages are often compressed and must first be decompressed, Unreal Package Decompressor by Gildor is a tool that can decompress most packages for you; for some games you need a specialized decompressor, see for example RLUPKTool.

How to contribute

  • Open an issue
  • Or make a pull-request by creating a fork of this repository, create a new branch and commit your changes to that particular branch, so that I can easily merge your changes.

Want to add support for a game? See adding support for new Unreal classes

Made with the help of UELib

Special thanks to