Pak File Management System

This section documents runtime pak file mounting and asset loading capabilities (UE5.2+).

Overview

UnrealCV supports dynamic loading of pak files at runtime, enabling:

  • On-demand asset loading: Load assets without restarting the game

  • DLC-like functionality: Package content in separate pak files

  • Asset pooling: Register pak assets to AssetPoolManager for random selection

  • Hot-swappable content: Mount/unmount paks during gameplay

Note

Pak file management requires cooked content. Pak files must be created using UE5’s packaging system with appropriate compression settings.

Pak File Requirements

  1. Cooked Content: Pak files must be cooked for the target platform

  2. Mount Point: Pak files need a valid mount point (e.g., /Game/)

  3. Loading Order: Use PakOrder for dependency management

Creating Pak Files

In UE5 Editor:

  1. Package your project: Platforms > Windows > Package Project

  2. Or use UnrealPak tool directly:

    UnrealPak.exe MyProject_Paks/MyPak.pak /Create=/Game/MyFolder

  3. Copy pak files to a location accessible at runtime

TCP Commands

Pak Management

vset /pak/mount [PakFilePath] [PakOrder=0]

Mount a pak file at runtime.

Arguments: - PakFilePath: Full path to the pak file - PakOrder: Loading order (higher = loaded later)

Example: vset /pak/mount D:/MyContent/MyAssets.pak 0

Returns: Mounted: D:/MyContent/MyAssets.pak (Order: 0)

vset /pak/unmount [PakFilePath]

Unmount a previously mounted pak file.

Example: vset /pak/unmount D:/MyContent/MyAssets.pak

vget /pak/mounted

Get list of all currently mounted pak files.

Returns: Newline-separated numbered list of pak file paths, starting at 1

Example output:

1. D:/MyContent/MyAssets.pak
2. D:/MyContent/Shared.pak
vget /pak/ismounted [PakFilePath|PakIndex]

Check if a pak file is currently mounted.

You can pass either a full pak file path or the logical index shown by vget /pak/mounted.

Returns: 1 if mounted, 0 if not

Pak Asset Operations

vset /pak/scan [MountPoint] [bForceRescan=1]

Scan assets in a mounted pak file.

Arguments: - MountPoint: Mount point path (e.g., /Game/) - bForceRescan: Force rescan even if already scanned

Example: vset /pak/scan /Game/ 1

vget /pak/load [AssetPath]

Load a specific asset from a mounted pak.

Arguments: - AssetPath: Full asset path (e.g., /Game/Assets/Car/BP_Car.uasset)

Returns: Loaded: /Game/Assets/Car/BP_Car.uasset (Class: Blueprint)

vget /pak/assets [PackagePath]

Get all assets in a package path.

Arguments: - PackagePath: Package path with wildcard (e.g., /Game/Assets/*)

Returns: Newline-separated list of asset paths

vget /pak/registered_paths [PakFilePath|PakIndex]

Get all package paths that can be resolved from a pak file using its mount point.

Arguments: - PakFilePath: Full path to the pak file - PakIndex: Logical index from vget /pak/mounted (1-based)

Returns: Newline-separated list of long package names

vget /pak/registered_status [PakFilePath|PakIndex]

Get all package paths resolved from a pak file along with existence status.

Arguments: - PakFilePath: Full path to the pak file - PakIndex: Logical index from vget /pak/mounted (1-based)

Returns: Newline-separated rows in the form PackagePath<TAB>found|missing<TAB>loadable|not_loadable[<TAB>Filename]

Asset Pool Integration

vset /pak/register [PackagePath] [Category]

Register assets from a pak file to AssetPoolManager.

Arguments: - PackagePath: Package path with wildcard (e.g., /Game/Assets/*) - Category: Asset pool category name

Example: vset /pak/register /Game/Foreground/* Foreground_Human

This makes assets available for random selection via SceneCompositionBPLib.

Available categories: - Foreground_Human - Human actors/characters - Foreground_Animal - Animal characters - Foreground_Vehicle - Vehicle actors - Foreground_Object - Object actors - Occluder_* - Occluding objects - Scene_* - Scene decoration

Blueprint API

PakMountBPLib provides Blueprint-accessible functions for pak management.

Mounting Functions

MountPakFile(PakFilePath, PakOrder) → bool

Mount a pak file from Blueprint.

Parameters:

  • PakFilePath – Full path to the pak file (string)

  • PakOrder – Loading order integer (default: 0)

Returns:

true if mounted successfully

UnmountPakFile(PakFilePath) → bool

Unmount a previously mounted pak file.

Parameters:

PakFilePath – Path of the pak file to unmount, or a mounted index

Returns:

true if unmounted successfully

GetMountedPakFiles() → array[string]

Get list of all currently mounted pak file paths.

Returns:

Array of pak file paths

IsPakFileMounted(PakFilePath) → bool

Check if a specific pak file is mounted.

Parameters:

PakFilePath – Path to check, or a mounted index

Returns:

true if mounted

Asset Loading Functions

ScanMountedAssets(MountPoint, bForceRescan)

Scan and register asset registry for a mount point.

Parameters:

  • MountPoint – Mount point path (e.g., /Game/)

  • bForceRescan – Force rescan even if already scanned

GetAllAssetsInPath(PackagePath, AssetClass) → array[string]

Get all assets in a package path.

Parameters:

  • PackagePath – Package path with optional wildcard

  • AssetClass – Optional class filter (e.g., UBlueprint::StaticClass())

Returns:

Array of asset paths

GetRegisteredPackagePathsInPakFile(PakFilePath) → array[string]

Get all long package names that can be resolved from a pak file.

Parameters:

PakFilePath – Full path to the pak file, or a mounted index

Returns:

Array of long package names

GetRegisteredPackageStatusInPakFile(PakFilePath) → array[string]

Get all resolved package paths from a pak file with existence status.

Parameters:

PakFilePath – Full path to the pak file, or a mounted index

Returns:

Array of status rows

LoadAssetFromPak(AssetPath, AssetClass) → UObject

Load a specific asset from pak.

Parameters:

  • AssetPath – Full asset path

  • AssetClass – Expected class (can be nullptr)

Returns:

Loaded UObject or nullptr

Asset Pool Integration

RegisterAssetsToAssetPool(PackagePath, Category) → bool

Register pak assets to AssetPoolManager.

Parameters:

  • PackagePath – Package path with wildcard

  • Category – Asset pool category name

Returns:

true if registration successful

Workflow Example

Step 1: Mount pak file

vset /pak/mount D:/Content/MyAssets.pak 0

# Check if mounted
vget /pak/mounted

Step 2: Scan for assets

vset /pak/scan /Game/ 1

# List all assets
vget /pak/assets /Game/MyAssets/*

Step 3: Register to asset pool

vset /pak/register /Game/MyAssets/* Foreground_Human

Step 4: Use in scene composition

Now assets are available for random selection via SceneCompositionBPLib:

SpawnRandomForeground(Category="Foreground_Human")

Common Issues

Asset not found after mounting

  • Ensure mount point path is correct

  • Call vset /pak/scan [MountPoint] 1 after mounting

  • Verify pak file was cooked for the correct platform

LoadAsset returns nullptr

  • Check that the asset path is exactly correct (case-sensitive)

  • Verify the asset class matches expected type

  • Ensure the asset is in a mounted pak file

Registration to asset pool fails

  • Confirm the category name is valid

  • Check that assets were scanned before registration

  • Verify the package path has wildcard (*) for multiple assets

See Also