Pak Rat

Pak Rat

Stop Guessing, Start Cooking: The Smart Way to Pack Assets.

Overview

Pak Rat builds a ready-to-use `.pak` mod from your own art through a simple step-by-step wizard — no command line, no manual repacking. Swap textures, swap pre-cooked meshes, cook your own 3D models with Unreal, pull originals out to edit, or combine mods you already have into one pak.

Requirements

• Retro Rewind installed via Steam. Pak Rat reads the game's base pak to pull the original assets it needs (and builds its texture/mesh lists from your copy on first run).

• Unreal Engine 5. 4 (optional) — only for the Cook Mesh mode. Install it free from the Epic Games Launcher. Everything else works without it.

Nothing else to install — the app is otherwise self-contained.

Running it

Double-click Pak-Rat.exe.

• First launch may show a Windows SmartScreen prompt ("Windows protected your PC") because the app isn't code-signed. Click More info → Run anyway.

• Keep `Pak-Rat.exe`, the `_internal` folder, and `data` folder together. Move the whole Pak-Rat folder as a unit. Deleting `_internal` breaks the app.

What it does

On Page 1 you pick a mode:

Regular Texture

Swap one or many textures — all packed into a single `.pak`.

1. Pick a texture from the dropdown (type to filter).

2. Choose a replacement PNG or DDS for it. Add as many more textures as you like, each with its own image.

3. Each image is automatically resized to its target's exact dimensions and re-encoded to the matching BC format.

4. Pak Rat injects them all and packs one `.pak`.

Mesh + Texture

Swap a pre-cooked mesh and the assets it depends on.

1. Pick the mesh, then its overlay texture.

2. Pak Rat walks the mesh's dependencies (materials → textures) and lists every slot on the Required Files page.

3. Provide your cooked `.uasset` replacement for each swappable slot (the `.uexp`/`.ubulk` sidecars are picked up automatically). Parent shaders are shown as "vanilla, not swappable"; shared assets are flagged.

4. Pak Rat packs everything into the `.pak`.

Cook Mesh from a 3D file  (needs Unreal Engine 5. 4)

Bring your own model in almost any format — Pak Rat cooks it for you.

1. On first use, Pak Rat downloads a portable Blender and builds a small cook project (one-time, cached in your user folder).

2. Pick the game mesh your model stands in for.

3. Choose your model file (FBX, OBJ, glTF/GLB, STL, PLY, DAE or .blend); add more meshes to pack together if you want.

4. Pak Rat converts it with Blender, cooks it with your installed Unreal Engine 5. 4, retargets it onto the game's real materials, and packs the `.pak`.

• This mode appears only when an Unreal Engine install is detected.

Extract Texture

Pull an original texture out of the game to use as a starting point.

1. Pick the texture from the dropdown (type to filter).

2. Pak Rat live-extracts the original and shows its spec + preview.

3. Choose a format:

• PNG — decoded, easy to edit in any image editor (recommended).

• DDS — the exact BC format + full mip chain, for a clean re-inject.

4. Pick where to save it. Pak Rat writes the file and opens the folder.

• Edit the PNG, then come back through Regular Texture to swap your version back in.

Combine Mods

Merge mods you already have into a single `.pak`.

1. Pak Rat lists the paks in your `~mods` folder; add any others with Add pak.

2. It shows every asset across them and flags conflicts (the same asset in more than one pak). Tick the assets you want; for conflicts, pick the winner.

3. Pak Rat merges your selection into one conflict-free `.pak`.

Finishing

When the `.pak` is built, name it, then choose:

• Deploy — installs it straight into Retro Rewind's `~mods` folder.

• Finish — saves it to your Documents and opens the folder.

Notes & limitations

• The texture/mesh lists are built from your own installed game on first run and cached. Texture list = the game's swappable `T_…_bc` base-colour textures; mesh list = the static meshes (`LA_`/`SM_`) under the game's mesh folder. Skeletal meshes (`SK_`) and virtual textures aren't supported.

• Cook Mesh needs a local Unreal Engine 5. 4 install (Epic Games Launcher) and downloads a portable