Repak GUI for STALKER 2

A graphical wrapper for repak — the Unreal Engine .pak file tool. Built specifically for STALKER 2 modding.

Before You Start

You need two things before using this tool:

1. The repak binary

The repak binary handles all pak/unpack operations. This GUI is just a wrapper around it.

• Pre-built releases already include repak — download from Releases
• From source: download repak from trumank/repak and place it in the same directory as repak_gui.py

2. The STALKER 2 AES encryption key (for unpacking game paks)

STALKER 2 game paks are AES-256 encrypted. You need the decryption key to unpack them.

Where to find the key:

• Search the STALKER 2 Modding Wiki or modding Discord servers for the current AES key
• The key is a 64-character hex string (e.g., 0x1A2B3C...)
• Paste it into the "AES-256 Key" field in the GUI

You do NOT need an AES key for:

• Unpacking mods made by other modders (most are unencrypted)
• Packing your own mods

3. Windows only: Oodle DLL

Windows users must place oo2core_9_win64.dll in the same directory as the executable.

Where to find it:

1. Go to your STALKER 2 install folder: Stalker2/Content/Paks/
2. Copy oo2core_9_win64.dll next to RepakGUI.exe

This is a proprietary Oodle compression library from Epic Games and cannot be bundled due to licensing.

Installation

Option A: Pre-built executable (recommended)

Download from Releases:

Platform	File	Notes
Windows	RepakGUI.exe	Needs oo2core_9_win64.dll alongside
Linux	RepakGUI-Linux	chmod +x RepakGUI-Linux then run

Option B: Run from source (Linux)

chmod +x run.sh
./run.sh

The launcher auto-detects your package manager and installs tkinter if missing.

Option C: Run with Python directly

python3 repak_gui.py

Requires Python 3.7+ and tkinter (usually bundled with Python).

How to Use

Setting the output folder

By default, output goes to your Downloads folder. To change it:

1. Click Set Output Folder (below the tabs)
2. Pick any folder — unpacked files go to <folder>/unpackedfiles/, packed files to <folder>/packedfiles/
3. Click Reset to go back to Downloads

The setting is saved between sessions.

Unpacking a game pak (extracting files)

1. Open the Unpack tab
2. Click Browse (or Ctrl+O) and select a .pak file
3. If it's an encrypted game pak, paste the AES key in the AES-256 Key field at the bottom
4. Click Unpack
5. Files go to <output folder>/unpackedfiles/<pakname>/

Packing a mod (creating a .pak)

1. Open the Pack tab
2. Click Browse and select your mod folder (must follow the game's directory structure)
3. Enter a pak name — use STALKER 2 naming convention: ~mods_yourmodname_P
4. Click Pack
5. Output goes to <output folder>/packedfiles/

Batch unpacking multiple paks

1. Open the Batch Unpack tab
2. Add Files or Add Folder to queue .pak files
3. Right-click the list to reorder (Move Up/Down) or remove entries
4. Click Unpack All
5. Press Escape to cancel at any time

Viewing pak contents without unpacking

1. Open the Info/List tab
2. Browse for a .pak file
3. Show Info for metadata, List Contents for file listing

STALKER 2 Modding Tips

Pak naming convention

Use the ~mods prefix for mod paks:

• Format: ~mods_modname_P.pak
• Example: ~mods_betterweapons_P.pak

This ensures mods load with correct priority.

Recommended workflow

1. Unpack the game pak containing the files you want to modify
2. Find and edit the relevant files
3. Recreate the game's directory structure in a new folder with only your changed files
4. Pack with ~mods_yourmod_P name
5. Place the .pak in Stalker2/Content/Paks/~mods/
6. Use find_conflicts.py to check compatibility with other mods

Detecting mod conflicts

python3 find_conflicts.py

Scans unpackedfiles/ for .cfg files that appear in multiple mods with different content. Copies conflicting versions into conflicts/ for side-by-side comparison.

Keyboard Shortcuts

Shortcut	Action
Ctrl+O	Browse for pak file
Ctrl+L	Clear log
Ctrl+E	Export log to file
Ctrl+Q	Quit
Escape	Cancel current operation

Updates

• Manual check: Help menu > Check for Updates
• Auto-check on startup: Disabled by default. Enable via Help menu > "Check for Updates on Startup"
• Updates are verified with SHA-256 checksums and a backup is created before applying

Output directories

Default output folder: ~/Downloads (configurable via Set Output Folder button).

Directory	Contents
<output folder>/unpackedfiles/	Extracted pak contents
<output folder>/packedfiles/	Created .pak files
conflicts/	Conflict analysis output (in script dir)
repak_gui.log	Operation log (rotated, 5MB max, in script dir)
repak_gui_config.json	Saved settings (in script dir)

Troubleshooting

Linux: "tkinter not found"

Install via your package manager:

• Arch: sudo pacman -S tk
• Debian/Ubuntu: sudo apt install python3-tk
• Fedora: sudo dnf install python3-tkinter
• openSUSE: sudo zypper install python3-tk

Or use ./run.sh which handles this automatically.

Windows: operation fails immediately

Make sure oo2core_9_win64.dll is in the same directory as the executable. See Before You Start.

"repak binary not found"

Place the repak binary (Linux) or repak.exe (Windows) in the same directory as the GUI.

Encrypted pak won't unpack

• Verify the AES key is correct (64 hex characters or base64)
• Make sure there are no leading/trailing spaces
• The key must match the game version — keys can change with game updates

Development

# Run tests
pip install pytest pytest-cov
pytest test_repak_gui.py -v

# With coverage
pytest test_repak_gui.py -v --cov=repak_gui --cov=find_conflicts

# Lint
pip install ruff
ruff check repak_gui.py find_conflicts.py

Credits

Built on top of repak by trumank. All pak/unpack functionality comes from repak — this project provides the graphical interface.

License

MIT