SN2 Mod Installer

Desktop helper for installing packaged Subnautica 2 LogicMods without manually copying and renaming Unreal chunk files every time.

Why it exists

Subnautica 2 mods packaged from Unreal output chunk files named like pakchunk15-Windows.pak, pakchunk15-Windows.ucas, and pakchunk15-Windows.utoc. For local testing, those files need to be copied into the game's LogicMods folder and renamed to the mod name.

This tool turns that repeated install step into a small UI: pick the packaged output folder, pick the game's LogicMods folder, enter the mod name/chunk id, and install.

Features

• Copies pak, ucas, and utoc files in one action.
• Renames packaged chunk files to the selected mod name.
• Installs into Subnautica2/Content/Paks/LogicMods/<ModName>.
• Remembers local paths, mod name, chunk id, launch preference, and window placement.
• Reopens maximized or normal depending on the last saved state.
• Prevents duplicate app windows.
• Optionally launches Subnautica 2 after install.
• Auto-detects common Steam library locations and the adjacent Unreal packaged output folder.

Local configuration

The app writes this ignored local file:

app/Install-SN2-Mod.settings.json

It stores machine-specific paths and UI state, so it should not be committed.

If no local settings exist, the app tries to find:

• packaged Unreal output at ../Subnautica2-Project/Paks/Windows/Subnautica2/Content/Paks;
• Subnautica 2 in common Steam library locations and libraryfolders.vdf.

If auto-detection misses your setup, use the Browse buttons once. The chosen paths are saved locally.

Scope

This was built for my own Subnautica 2 modding workflow, but it should be useful for other local LogicMods testing setups as long as the packaged Unreal output uses the same pakchunk<ID>-Windows.* naming pattern and the game install path can be selected manually.

Run

Double-click the root launcher:

SN2 Mod Installer.vbs

The implementation lives under app/ so the root folder stays clean.

Direct run:

python .\app\Install-SN2-Mod.pyw