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

Module	Version	License

• Usage: See the documentation for more examples.

    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.

Name	Engine	Package	State	Script	Audio	Texture
Unreal Engine 1				✅	✅	✅
Unreal	100-226	61/000		✅	✅	✅
Star Trek: The Next Generation: Klingon Honor Guard	219	61/000		✅
X-COM: Alliance	200-220	61/000	Bad output at the start of functions (BeginFunctionToken)	✅
Dr. Brain: Action Reaction	224	63-68/000		✅
Nerf Arena Blast	225	63-68/000		✅
The Wheel of Time	225:WoT	63-68/000		✅
Unreal Mission Pack: Return to Na Pali	226b	68/000		✅
Unreal Tournament	338-436	68-69/000		✅	✅	✅
Deus Ex	400-436	68/000		✅
Jazz Jackrabbit 3D	400	68/000		✅
Duke Nukem Forever (2001)	613	68/002	UStruct offsets are off leading to bad output code	✅
Rune	400	69/000		✅
Unrealty	405	69/000		✅
X-COM: Enforcer	420	69/000		✅
Tactical Ops: Assault on Terror	436	69/000		✅
Star Trek: Deep Space Nine: The Fallen	338	73/000		✅
Harry Potter and the Sorcerer's Stone	436	76/000		✅
Harry Potter and the Chamber of Secrets	433	79/000		✅
Disney's Brother Bear	433	80/000	Link	✅
Mobile Forces	436	81-83/000, 69		✅
Clive Barker's Undying	420	72-85/000	Versions 72 to 83 are not auto detected.	✅	✅
Thief: Deadly Shadows	777:Flesh	95/133	Thanks in part to @hanfling; LinkedData not supported	✅
Deus Ex: Invisible War	777:Flesh	95/069	Thanks in part to @hanfling; LinkedData not supported	✅
Unreal Engine 2				✅	✅	✅
XIII	829	100/058		✅
Tom Clancy's Splinter Cell	829	100/017		✅
Tom Clancy's Splinter Cell: Chaos Theory	829	100/120:SCX, 175/000:ShadowStrike	(PC) demo version, Versus mode not supported	✅
Tom Clancy's Splinter Cell: Double Agent	829	100/167:SCX, 275/000:ShadowStrike	(PC) Offline mode version, Online mode not supported	✅
Tom Clancy's Splinter Cell: Blacklist	829	102/116:LEAD	In part thanks to @shryder. Third-party decompression is required	✅
Tom Clancy's Rainbow Six 3: Raven Shield	600-927	118/012-014		✅	✅
Postal 2: Paradise Lost	1417	118/002		✅
Unreal Tournament 2003	1077-2225	119/025		✅	✅	✅
Devastation	600-?	118-120/004-008		✅
Unreal II: The Awakening	829-2001	126/2609		✅
Unreal II: eXpanded MultiPlayer	2226	126/000	Custom features are not decompiled	✅
Desert Thunder	2226	126/000		✅
Land of the Dead: Road to Fiddler's Green	2226	126/001		✅
Unreal Tournament 2004	3120-3369	128/029		✅	✅	✅
America's Army 2	3339	128/032:033	2.5, 2.6, 2.8	✅
America's Army (Arcade)	3339	128/032	2.6	✅
Red Orchestra: Ostfront 41-45	3323-3369	128/029		✅	✅
Killing Floor	3369	128/029		✅	✅
Shadow Ops: Red Mercury	2110	129/010		✅
Vanguard: Saga of Heroes	2226	129/035		✅
Harry Potter and the Prisoner of Azkaban	2226	129/000	Link	✅
Shrek 2	2226	129		✅
Shark Tale	2226	129/003		✅
Lemony Snicket's A Series of Unfortunate Events	2226	129/003		✅
Swat 4	2226:Vengeance	129/027		✅
Stargate SG1: The Alliance	4180	130/004		✅
Tribes: Vengeance	2226:Vengeance	130/027		✅
Bioshock	2226:Vengeance	130-141/056		✅
Arctic Combat	3369	134/038-039	Thanks to @EDITzDev. Third-party decompression is required	✅	✅	✅
Star Wars: Republic Commando	2226	134-159/001		✅
Men of Valor	926	137/000	PC	✅
Bioshock 2	2226:Vengeance	143/059		✅
Advent Rising	2226	143-146/007		✅	✅
Unreal Championship 2: Liandri Conflict	3323	151/002	Third-party	✅
The Chronicles of Spellborn	3323	159/029		✅
Duke Nukem Forever (2011)	Unknown	156/036	Extraction is required	✅
Unreal Engine 3				✅	✅	✅
RoboHordes	Unknown	198-200/000		✅	✅
Tom Clancy's Rainbow Six: Vegas	Unknown	241/066		✅
Tom Clancy's Rainbow Six: Vegas 2	Unknown	241/071		✅
Tom Clancy's EndWar	Unknown	329/000		✅
Roboblitz	2306	369/006		✅	✅
Stranglehold	2605	375/025		✅
Mass Effect (Xbox 360)	2674	391/092	Xenon	✅
Warmonger: Operation Downtown Destruction	2859	419/003		✅
Medal of Honor: Airborne	2859	421/011		✅
Frontlines: Fuel of War	2917	433/052		✅
Army of Two	3004	445/079	Overall quality has not been verified	✅
Mortal Kombat Komplete Edition	2605	472/046		✅
Stargate Worlds	3004	486/007		✅
Gears of War	3329	490/009		✅
Mass Effect (Windows)	3240	491/1008(~112)	PC	✅
Huxley	3240	496/016-023	Contributed by @EDITzDev	✅	✅
Robert Ludlum's The Bourne Conspiracy		511/039		✅
Transformers: War for Cybertron		511/144,145	PC, PS3, Xenon	✅
Unreal Tournament 3	3809	512/000		✅
Mirrors Edge	3716	536/043		✅
Alpha Protocol	3857	539/091		✅
APB: All Points Bulletin	3908	547/028-032		✅
X-Men Origins: Wolverine	4206	568/101	Overall quality has not been verified	✅
Gears of War 2	4638	575/000		✅
CrimeCraft	4701	576/005		✅
Batman: Arkham Asylum	4701	576/21	Contributed by @etkramer	✅
Medal of Honor (2010)	100075???	581/058	Bad byte-codes	✅
Singularity	4869	584/126		✅
MoonBase Alpha	4947	587/000		✅
Saw	Unknown	584/003		✅
The Exiled Realm of Arborea or TERA	4206	610/014		✅
Monday Night Combat	5697	638/000		✅
DC Universe Online	5859	638/6405	Contributed by @theFoof	✅
Unreal Development Kit	5860-12791	664-868		✅	✅	✅
Blacklight: Tango Down	6165	673/002		✅
Dungeons & Dragons: Daggerdale	6165	674/000		✅
Dungeon Defenders	6262	678/002		✅	✅
Mass Effect 3 (Windows)	6383	684/194	PC (platform must be set to Console)	✅
Mass Effect: Legendary Edition (Windows)	6383	684/171	PC (platform must be set to Console)	✅
Alice Madness Returns	6760	690/000		✅
The Ball	6699	706/000		✅
Game of Thrones	6829	727/000		✅
Bioshock Infinite	6829	727/075		✅
Bulletstorm	7052	742/029		✅
Red Orchestra 2: Heroes of Stalingrad	7258	765/Unknown		✅
Rising Storm 2: Vietnam	7258	765/771		✅
Aliens: Colonial Marines	4170	787/047		✅
Infinity Blade 1	7595	788/001	Console	✅
Dishonored	9099	801/030		✅
Tribes: Ascend	7748	805/Unknown		✅
Tony Hawk's Pro Skater HD				✅
Rock of Ages	7748	805/000		✅
Batman: Arkham City	7748	805/101		✅
Batman: Arkham Origins	7748	807/138	Not verified	✅
Sanctum	7876	810/000		✅
AntiChamber	7977	812/000		✅
Waves	8171	813/000		✅
Super Monday Night Combat	8364	820/000		✅
Gears of War 3	8653	828/000		✅
Quantum Conundrum	8623	832/32870		✅
Borderlands	4871	Unknown		✅
Borderlands 2	8623/0023	832/056		✅
Borderlands: Game of the Year Enhanced	5001/0001	832/058		✅
Remember Me	8623	832/021		✅
Gears of War: Ultimate Edition	3340	835/056	Actual package version is 490; thanks to @PaoloTK	✅
Gears of War: Reloaded	3340	835/076	Actual package version is 490; thanks to @PaoloTK	✅
The Haunted: Hells Reach	8788	841/000		✅
Asura's Wrath	8788	841/000	-zlib; platform needs to be set to console.	✅
Blacklight Retribution	8788-10499	841-864/002		✅
Infinity Blade 2	9059	842-864/001	Console	✅
Q.U.B.E	8916	845/000		✅
DmC: Devil May Cry	8916	845/004		✅
XCOM: Enemy Unknown	8916	845/059		✅
XCOM 2: War of the Chosen	8916	845/120	Contributed by @robojumper	✅
Gears of War: Judgement	10566	846/000		✅
Transformers: Fall of Cybertron		846(~587)/181		✅
Deadpool		846(~587)/181		✅
InMomentum	8980	848/000		✅
Unmechanical	9249	852/000		✅
Deadlight	9375	854/000		✅
Land of the Dead	9375	854/000		✅
Borderlands Legends	9505	859/000	iOS; platform needs to be set to console	✅
Ravaged	9641	859/000		✅
The Five Cores	9656	859/000		✅
Painkiller HD	9953	860/000		✅
Chivalry: Medieval Warfare	10246	860/000		✅
Hawken	10681	860/004		✅
Rocket League	10897	867/009 (868/032 has not been tested)	Decryption required	✅
Styx: Master of Shadows	10499	860/004		✅
Batman: Arkham Knight		863/32995	Not verified	✅
Gigantic: Rampage Edition	19100	867/010	Contributed by @HyenaCoding	✅
Infinity Blade 3		868/000	Console	✅
Guilty Gear Xrd	10246	868/003	Decryption required	✅
Outlast	12046	868/003		✅
Might & Magic Heroes VII	12161	868/004	(Signature and custom features are not supported)	✅
Bombshell	11767	870/000		✅
Orcs Must Die! Unchained	20430	870/000		✅
Gal*Gun: Double Peace	10897	871/000		✅
Battleborn	8623/1055	874/078		✅
A Hat in Time	12097	877-893/005	Contributed by @Un-Drew	✅
Bulletstorm: Full Clip Edition	12212	877/041		✅
Blue Estate The Game	10246	893/000		✅
Shadow Complex Remastered	10897	893/001		✅
Borderlands 2 VR	8637/0029	895/046		✅
Soldier Front 2	6712	904/009		✅
Rise of the Triad	10508	Unknown		✅
Sherlock Holmes: Crimes and Punishments	10897	Unknown		✅
Alien Rage	7255	Unknown		✅

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

• UnrealScript to C# Conversion and Mirror's Edge Decompiled
• Duke Nukem Forever: Enhanced
• UE3 Shader Cache Patcher
• UnrealFlagEditor
• Mir Eternal - Modified UELib with support for saving properties.

Special thanks to

• Epic Games for UDN: Packages (general package format)
• Antonio Cordero Balcazar for UTPT (game support) and documentation (format)
• Dmitry Jemerov for unhood (early UE3 format)
• Konstantin Nosov for providing help and UE Viewer (game support)
• Contributors