UAssetManager

class Engine Since 4.17

Inherits: UObjectBase › UObjectBaseUtility › UObject › UAssetManager

#include "Engine/AssetManager.h"

Description

The engine singleton that manages primary asset discovery, async loading, bundle state, and chunked DLC. Subclass it in Project Settings to add game-specific asset management logic.

Caveats & Gotchas

• Call UAssetManager::GetIfInitialized() instead of Get() if you need to check if it's been set up — Get() was deprecated in UE 5.3.
• Primary assets must be registered in the Asset Manager settings (Project Settings → Asset Manager) or in your custom UAssetManager subclass.
• LoadPrimaryAsset is async by default — the callback fires on the next tick or later. Do not use the result immediately after the call without checking handle validity.
• Bundles are the recommended way to manage what gets loaded for a given game state (e.g. only load combat art when in combat).

Signature

class UAssetManager : public UObject

Example

Async load a primary asset C++

FPrimaryAssetId AssetId(TEXT("WeaponData"), TEXT("Sword_01"));
TArray<FName> Bundles;
UAssetManager::GetIfInitialized()->LoadPrimaryAsset(
    AssetId,
    Bundles,
    FStreamableDelegate::CreateUObject(this, &AMyClass::OnWeaponLoaded)
);

Functions (105)

Utility 6 Asset Directory 17 Asset Loading 14 Asset Lookup 7 Asset Scanning 12 Bundle State 6 Chunk Management 7 Debugging 7 Initialization 12 Management Rules 8 Primary Assets 9

Utility

6 ▼

Access	Type	Name	Description
public	function	UAssetManager::CreatePrimaryAssetIdFromChunkId	Wraps a chunk index into a PrimaryAssetId of PackageChunkType, a virtual type that never loads data off disk.
public	function	UAssetManager::ExtractChunkIdFromPrimaryAssetId	Extracts the chunk index back out of a PrimaryAssetId created by CreatePrimaryAssetIdFromChunkId.
public	function	UAssetManager::GetContentRootPathFromPackageName	Returns the root mount path for a package name or path — for example /Game/MyPackage returns /Game/.
public	function	UAssetManager::GetEncryptionKeyAssetTagName	Returns the asset registry tag name under which encrypted primary assets store their encryption key GUID, for use when querying asset registry tag data.
public	function	UAssetManager::GetNormalizedPackagePath	Returns a normalized copy of a package path, removing duplicate slashes and adding or stripping a final trailing slash as requested.
public	function	UAssetManager::NormalizePackagePath	Normalizes a package path for use in the Asset Manager, removing duplicate slashes and adding or stripping a final trailing slash as requested.

Asset Directory

17 ▼

Access	Type	Name	Description
public	function	UAssetManager::GetPrimaryAssetData	Gets the FAssetData for a primary asset with the specified type/name.
public	function	UAssetManager::GetPrimaryAssetDataList	Gets the list of all FAssetData for every primary asset registered under a given type.
public	function	UAssetManager::GetPrimaryAssetIdForObject	Checks whether the passed-in object is a registered primary asset and if so returns its id, otherwise returns an invalid FPrimaryAssetId.
public	function	UAssetManager::GetPrimaryAssetIdForPath	Checks whether the passed-in object path is a registered primary asset and if so returns its id, otherwise returns an invalid FPrimaryAssetId.
public	function	UAssetManager::GetPrimaryAssetIdList	Gets the list of all FPrimaryAssetId values registered for a given primary asset type, returning true if any were found.
public	function	UAssetManager::GetPrimaryAssetObject	Gets the in-memory UObject for a primary asset id, returning nullptr if it isn't currently loaded.
public	function	UAssetManager::GetPrimaryAssetObjectClass	Templated helper that gets the in-memory class object for a primary asset id, useful when the primary asset is itself a Blueprint class.
public	function	UAssetManager::GetPrimaryAssetObjectList	Gets the list of all currently loaded objects for a primary asset type.
public	function	UAssetManager::GetPrimaryAssetPath	Gets the FSoftObjectPath for a primary asset type and name, returning an invalid path if the asset isn't found.
public	function	UAssetManager::GetPrimaryAssetPathList	Gets the list of all FSoftObjectPaths registered for a given primary asset type, returning true if any were found.
public	function	UAssetManager::GetPrimaryAssetTypeInfo	Gets metadata for a specific primary asset type, returning false if that type hasn't been registered.
public	function	UAssetManager::GetPrimaryAssetTypeInfoList	Gets the list of metadata for every primary asset type currently registered with the asset manager.
public	function	UAssetManager::InvalidatePrimaryAssetDirectory	Marks the cached primary asset directory as needing a rescan, without rescanning immediately.
public	function	UAssetManager::RefreshPrimaryAssetDirectory	Refreshes the entire set of primary asset data, useful in the editor after assets have changed dramatically.
public	function	UAssetManager::ExtractPrimaryAssetIdFromData	Parses an FAssetData to derive the primary asset type and name from it, working even for assets that aren't in the primary asset directory (for example, ones excluded from scanning).
public	function	UAssetManager::GetPrimaryAssetIdForData	Returns the primary asset id for the given FAssetData, only working if that asset is already present in the asset directory.
public	function	UAssetManager::GetPrimaryAssetIdForPackage	Checks whether the given package has a registered primary asset id, useful when only the package name is available rather than a full object path.

Asset Loading

14 ▼

Access	Type	Name	Description
public	function	UAssetManager::ChangeBundleStateForMatchingPrimaryAssets	Changes bundle state across every currently loaded primary asset that has the given OldBundles, replacing them with NewBundles — useful for global state changes like switching level-of-detail or platform bundle sets.
public	function	UAssetManager::ChangeBundleStateForPrimaryAssets	Adds and removes bundle state on a set of already-loaded primary assets, streaming in newly required bundle assets and calling the delegate once the change completes.
public	function	UAssetManager::GetPrimaryAssetHandle	Returns the streamable handle tracking the load of a primary asset, so its progress can be polled or waited on.
public	function	UAssetManager::LoadAssetList	Loads a list of asset paths that are not primary assets, using the same StreamableManager the AssetManager uses internally.
public	function	UAssetManager::LoadPrimaryAsset	Single-asset convenience wrapper around LoadPrimaryAssets for loading just one primary asset and its bundles.
public	function	UAssetManager::LoadPrimaryAssets	Starts an async load of the given primary assets and bundles, keeping them resident in memory until explicitly unloaded, and calls the delegate when loading completes.
public	function	UAssetManager::LoadPrimaryAssetsWithType	Loads every primary asset registered under a given type and bundle set, useful for bulk-loading a whole asset category such as during cooking or level warm-up.
public	function	UAssetManager::PreloadPrimaryAssets	Starts an async load of the given primary assets into a specific bundle state without marking them as officially Loaded.
public	function	UAssetManager::UnloadPrimaryAsset	Single-asset convenience wrapper around UnloadPrimaryAssets for releasing one previously loaded primary asset.
public	function	UAssetManager::UnloadPrimaryAssets	Unloads a list of primary assets that were previously loaded through the asset manager, releasing them if nothing else is keeping them in memory.
public	function	UAssetManager::UnloadPrimaryAssetsWithType	Unloads every currently loaded Primary Asset of the given type in one call.
public	function	UAssetManager::DownloadAssetList	Downloads a list of non-primary asset paths into the download cache without loading them into memory.
public	function	UAssetManager::PredownloadPrimaryAssets	Downloads the packages for a set of primary assets into the download cache using IoStoreOnDemand, without loading them into memory.
public	function	UAssetManager::RecursivelyExpandBundleData	Expands references inside the given bundle data that point at other primary assets' bundles, pulling their contents in recursively.

Asset Lookup

7 ▼

Access	Type	Name	Description
public	function	UAssetManager::GetAssetDataForPath	Gets the FAssetData at a specific path, correctly handling redirectors and Blueprint classes along the way.
public	function	UAssetManager::GetAssetPathForData	Converts an FAssetData into an FSoftObjectPath, appending the _C suffix automatically when the asset is a Blueprint class.
public	function	UAssetManager::SearchAssetRegistryPaths	Helper that searches the asset registry for AssetData matching the given FAssetManagerSearchRules, combining directory scope, wildcard patterns, and base class filtering.
public	function	UAssetManager::DoesAssetMatchSearchRules	Checks whether a single asset passes the restrictions defined in Rules.
public	function	UAssetManager::ExtractSoftObjectPaths	Walks a class or struct's reflected properties and extracts every FSoftObjectPath found, including those nested inside arrays, maps, and sub-structs.
public	function	UAssetManager::GetRedirectedAssetPath	Reads the Asset Manager settings for specifically redirected asset paths and returns the current path.
public	function	UAssetManager::IsAssetDataBlueprintOfClassSet	Checks whether the given asset data is a Blueprint whose base class appears in ClassNameSet.

Asset Scanning

12 ▼

Access	Type	Name	Description
public	function	UAssetManager::AddDynamicAsset	Registers a runtime-only primary asset that has no on-disk FAssetData, giving it a path and bundle state anyway.
public	function	UAssetManager::GetAssetSearchRoots	Returns all registered game asset search roots, including /Game by default plus any added dynamically via AddAssetSearchRoot.
public	function	UAssetManager::ScanPathForPrimaryAssets	Single-path convenience wrapper around ScanPathsForPrimaryAssets.
public	function	UAssetManager::ScanPathsForPrimaryAssets	Scans a list of file system paths and registers any matching assets of the given type into the primary asset directory.
public	function	UAssetManager::AddAssetSearchRoot	Registers a new virtual asset search root so paths starting with it can be scanned and resolved like /Game.
public	function	UAssetManager::ExpandVirtualPaths	Expands a list of paths that potentially use virtual asset roots into real directory and package paths.
public	function	UAssetManager::PopBulkScanning	Ends a bulk scanning batch started with PushBulkScanning, running the deferred bookkeeping that was skipped during the batch.
public	function	UAssetManager::PushBulkScanning	Marks the start of a batch of ScanPathsForPrimaryAssets calls so the AssetManager can defer expensive per-scan bookkeeping until the matching PopBulkScanning.
public	function	UAssetManager::Register_OnAddedAssetSearchRoot	Registers a callback that fires whenever a new asset search root is mounted at runtime, such as from a plugin or pak file.
public	function	UAssetManager::RemovePrimaryAssetType	Removes an entire primary asset type and all of its scanned assets from the directory.
public	function	UAssetManager::RemoveScanPathsForPrimaryAssets	Removes primary assets found under the given paths from the asset directory, undoing a prior ScanPathsForPrimaryAssets call.
public	function	UAssetManager::Unregister_OnAddedAssetSearchRoot	Removes a previously registered callback for the new-asset-search-root notification.

Bundle State

6 ▼

Access	Type	Name	Description
public	function	UAssetManager::GetAssetBundleEntries	Appends every FAssetBundleEntry registered under BundleScope to OutEntries, covering all bundles defined on that primary asset at once.
public	function	UAssetManager::GetAssetBundleEntry	Returns the single FAssetBundleEntry matching the given scope and bundle name.
public	function	UAssetManager::GetPrimaryAssetBundleStateMap	Fills BundleStateMap with a full snapshot of every loaded primary asset mapped to its active bundle list, in a single call.
public	function	UAssetManager::GetPrimaryAssetLoadList	Fills OutAssetLoadList with the object paths that would need to be loaded for a primary asset under the given bundle list, without loading them.
public	function	UAssetManager::GetPrimaryAssetLoadSet	Fills OutAssetLoadSet with the unique object paths that would need to be loaded for a primary asset under the given bundle list, without actually loading them.
public	function	UAssetManager::GetPrimaryAssetsWithBundleState	Fills PrimaryAssetList with every primary asset that is loaded or being loaded and whose bundle state matches the required/excluded bundle filters.

Chunk Management

7 ▼

Access	Type	Name	Description
public	function	UAssetManager::AcquireResourcesForAssetList	Acquires the platform chunks required to install the given assets, then invokes CompleteDelegate.
public	function	UAssetManager::AcquireResourcesForPrimaryAssetList	Acquires the platform chunks needed for every bundle of the given primary assets, then invokes CompleteDelegate.
public	function	UAssetManager::FindMissingChunkList	Checks which platform chunks the given assets belong to and reports any that aren't currently mounted, separating chunks that can still be installed from ones that are missing entirely.
public	function	UAssetManager::GetCachedPrimaryAssetEncryptionKeyGuid	Gets the encryption key guid attached to a primary asset, which is invalid if the asset isn't encrypted.
public	function	UAssetManager::GetPakChunkIdToStringMapping	Allows the asset manager to override a pak chunk id with a string name instead of an integer, used at cook time to name the generated pak chunk files.
public	function	UAssetManager::GetPakStringToChunkIdMapping	Helper to get the chunk id based on the string override for a pak chunk, the inverse of GetPakChunkIdToStringMapping.
public	function	UAssetManager::GetResourceAcquireProgress	Reports chunk download/install progress across all outstanding AcquireResources requests, giving a simple acquired-out-of-requested count.

Debugging

7 ▼

Access	Type	Name	Description
public	function	UAssetManager::DumpAssetRegistryInfo	Logs a summary of the asset registry's contents to the output log, for diagnosing asset scanning and registry state issues.
public	function	UAssetManager::DumpAssetTypeSummary	Dumps a summary of all managed Primary Asset types to the log, including counts per type.
public	function	UAssetManager::DumpBundlesForAsset	Shows a list of all asset bundles registered for the specified Primary Asset, identified by its Primary Asset Id string (for example Map:Entry).
public	function	UAssetManager::DumpLoadedAssetState	Dumps a list of currently loaded asset bundles to the log.
public	function	UAssetManager::DumpReferencersForPackage	Logs the list of primary assets that manage each given package to the output log, useful for tracing why an asset is included in a cook or chunk.
public	function	UAssetManager::GetAllReferencersForPackage	Finds all packages that reference any of the given packages, recursing up the dependency graph to the given depth.
public	function	UAssetManager::WriteCustomReport	Helper function to write out asset reports, such as those generated by custom auditing tools built on top of the asset manager.

Initialization

12 ▼

Access	Type	Name	Description
public	function	UAssetManager::Get	Returns the current global AssetManager singleton.
public	function	UAssetManager::IsInitialized	Returns true once the global AssetManager singleton has been constructed.
public	function	UAssetManager::CallOrRegister_OnAssetManagerCreated	Registers a delegate to run once the AssetManager singleton has been created, invoking it immediately if the singleton already exists.
public	function	UAssetManager::CallOrRegister_OnCompletedInitialScan	Registers a delegate to run once the AssetManager's initial startup scan of all primary asset types has finished, invoking it immediately if the scan already completed.
public	function	UAssetManager::GetAssetRegistry	Returns the asset registry instance used by this asset manager, avoiding a separate module lookup.
public	function	UAssetManager::GetIfInitialized	Returns the current AssetManager singleton if it has already been constructed, or nullptr otherwise.
public	function	UAssetManager::GetSettings	Returns the project's Asset Manager settings object, sourced from the Asset Manager section of Project Settings / DefaultGame.
public	function	UAssetManager::GetStreamableManager	Returns the FStreamableManager instance owned by the AssetManager singleton, which the AssetManager uses internally for all primary asset streaming.
public	function	UAssetManager::HasInitialScanCompleted	Returns true once the AssetManager has finished its startup scan of all configured primary asset types.
public	function	UAssetManager::FinishInitialLoading	Finishes initial loading, called automatically from the end of UEngine::Init() once the startup asset scan has completed.
public	function	UAssetManager::GetTimerManager	Returns a timer manager safe to use for asset-loading-related actions, backed by the editor or game instance timer manager depending on context.
public	function	UAssetManager::StartInitialLoading	Begins the initial scan of primary asset types, called automatically from UEngine::InitializeObjectReferences.

Management Rules

8 ▼

Access	Type	Name	Description
public	function	UAssetManager::ApplyCustomPrimaryAssetRulesOverride	Applies a single custom primary asset rule override, matching assets of a type by an optional directory and filter string.
public	function	UAssetManager::GetManagedPackageList	Returns the list of asset packages that a given primary asset manages, meaning packages that should be included in the same chunk/cook as this asset.
public	function	UAssetManager::GetPackageCookRuleManagers	Returns the primary assets that determine whether a package is included in the cook, along with whether each reference is direct or indirect.
public	function	UAssetManager::GetPackageManagers	Returns every primary asset that manages a package in any way, whether through chunk assignment or cook inclusion.
public	function	UAssetManager::GetPrimaryAssetRules	Returns the effective management rules for a primary asset, merging any per-asset override on top of its type's default rules.
public	function	UAssetManager::SetPrimaryAssetRules	Overrides the management (cook/chunk/priority) rules for one specific primary asset, taking precedence over its type's default rules.
public	function	UAssetManager::SetPrimaryAssetRulesExplicitly	Overrides individual fields of a primary asset's management rules using explicit per-field override flags, instead of replacing the entire rules struct at once as SetPrimaryAssetRules does.
public	function	UAssetManager::SetPrimaryAssetTypeRules	Changes the default cook/chunk/priority management rules applied to every primary asset of a given type, unless overridden individually via SetPrimaryAssetRules.

Primary Assets

9 ▼

Access	Type	Name	Description
public	function	UAssetManager::ScanPathsSynchronous	Requests that the asset registry synchronously scan a list of directories or specific assets, blocking until the scan completes.
public	function	UAssetManager::DeterminePrimaryAssetIdForObject	Used when bShouldManagerDetermineTypeAndName is enabled in Asset Manager settings to compute a Primary Asset Id for objects that don't implement their own IPrimaryAssetObject-style logic.
public	function	UAssetManager::GetPreviousPrimaryAssetIds	Reads the redirector list and returns every previous Primary Asset Id that now redirects to NewId.
public	function	UAssetManager::GetRedirectedPrimaryAssetId	Tries to redirect a Primary Asset Id using the redirector list configured in the project's Asset Manager settings.
public	function	UAssetManager::LoadRedirectorMaps	Parses the primary asset id and asset path redirector lists from the Asset Manager settings into the lookup maps used by GetRedirectedPrimaryAssetId and GetRedirectedAssetPath.
public	function	UAssetManager::OnAssetRegistryAvailableAfterInitialization	Called when a new asset registry (for example a plugin or DLC registry) becomes available after the engine has already initialized.
public	function	UAssetManager::RegisterSpecificPrimaryAsset	Manually registers a new or updated Primary Asset outside of the normal directory-scan flow.
public	function	UAssetManager::ShouldScanPrimaryAssetType	Returns true if the specified Primary Asset type info should be scanned during directory scans.
public	function	UAssetManager::WarnAboutInvalidPrimaryAsset	Logs a warning that a primary asset id is missing or invalid, but only once per id for the session.

Version History

Introduced in: 4.17

Version	Status	Notes
5.6	stable	—

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