unreal.UsdAssetCache

class unreal.UsdAssetCache(outer: Object | None = None, name: Name | str = 'None')

Bases: Object

Owns the assets generated and reused by USD Stages, allowing thread-safe retrieval/storage.

C++ Source:

  • Plugin: USDImporter

  • Module: USDClasses

  • File: USDAssetCache2.h

Editor Properties: (see get_editor_property/set_editor_property)

  • asset_storage (Map[str, Object]): [Read-Only] Main hash to asset storage for all assets that we’re currently using and shouldn’t be GC’d

  • persistent_asset_storage_size_mb (double): [Read-Write] This limit specifies how much size is allocated to storing all persistent assets (i.e. assets that will be saved to disk, even if unused by any stage). Set this to 0 to disable persistent asset storage. This has no effect on temporary asset caches (e.g. the ones automatically generated when opening a stage without an asset cache asset assigned)

  • unreferenced_asset_storage_size_mb (double): [Read-Write] The asset cache will always retain all currently used assets. In addition to that, this limit specifies how much size is allocated to storing assets that remain only for the current session and that aren’t being used by any stage. Set this to 0 to disable storing unreferenced assets.

add_asset_reference(asset, referencer) → bool

Adds a new UObject referencer to a particular asset, returning true if the operation succeeded.

Assets will not be evicted or removed from the cache while the referencer is registered. Note that internally the cache keeps FObjectKey structs constructed from the referencers, instead of direct pointers to them.

Parameters:
Return type:

bool

cache_asset(hash, asset, referencer=None) → None

Adds an asset to the cache attached to a particular hash, and optionally registering a referencer

Parameters:
can_remove_asset(hash) → bool

Returns true if the asset with the given hash can be removed from the cache. It will return false in case the asset is still being used, either by another consumer asset or directly by some referencer.

Parameters:

hash (str) –

Return type:

bool

get_all_asset_hashes() → Array[str]

Returns all asset hashes tracked by the asset cache, for all storage types. This includes unloaded persistent assets

Return type:

Array[str]

get_all_cached_asset_paths() → Array[str]

Returns all asset paths tracked by the asset cache, for all storage types. (e.g. “/Game/MyTextures/RedBrick.RedBrick”). This includes unloaded persistent assets

Return type:

Array[str]

get_all_loaded_assets() → Array[Object]

Returns all assets that are currently loaded in the asset cache. This will not include persistent assets that haven’t been loaded yet.

Return type:

Array[Object]

get_cached_asset(hash) → Object

Returns an asset associated with a particular Hash. If the asset is persistent, unloaded and the “USD.OnDemandCachedAssetLoading” cvar is true, this may cause the asset to be read from the asset cache’s file on disk.

Parameters:

hash (str) –

Return type:

Object

get_hash_for_asset(asset) → str

Returns the hash associated with an asset, in case we own it. Returns the empty string otherwise. Note: This has O(1) time complexity.

Parameters:

asset (Object) –

Return type:

str

get_num_assets() → int32

Returns how many assets are tracked by the asset cache in total (summing up persistent, referenced and unreferenced storage)

Return type:

int32

is_asset_owned_by_cache(asset_path) → bool

Returns true in case the asset at AssetPath is tracked by the cache in any way (persistent asset, unreferenced or referenced). An example AssetPath would be “/Game/MyTextures/RedBrick.RedBrick”.

Parameters:

asset_path (str) –

Return type:

bool

property persistent_asset_storage_size_mb: float

[Read-Write] This limit specifies how much size is allocated to storing all persistent assets (i.e. assets that will be saved to disk, even if unused by any stage). Set this to 0 to disable persistent asset storage. This has no effect on temporary asset caches (e.g. the ones automatically generated when opening a stage without an asset cache asset assigned)

Type:

(double)

refresh_storage() → None

Updates which assets belong to each storage type. You must call this in case you perform direct operations on the asset cache, after those operations are fully complete.

remove_all_asset_references(referencer) → bool

Removes the particular referencer to all assets tracked by the cache, if it was a referencer to any of them. Returns true if at least one asset referencer count was altered by this.

Parameters:

referencer (Object) –

Return type:

bool

remove_asset(hash) → Object

If an asset is associated with Hash, it will be returned and the asset cache will stop tracking this asset entirely. Returns nullptr otherwise. See CanRemoveAsset.

WARNING: The asset will still be outer’d to the asset cache, however. The caller is in charge of properly placing the asset at a new Outer object.

Parameters:

hash (str) –

Return type:

Object

remove_asset_reference(asset, referencer=None) → bool

Removes an UObject referencer from a particular asset, returning true if the operation succeeded. If no specific Referencer is provided, all referencers to Asset will be removed.

Parameters:
Return type:

bool

reset() → None

Discards all tracked assets across all storage types

touch_asset(asset, referencer=None) → bool

Marks the provided asset as being used at this point, optionally adding a specific referencer. This is useful because the asset cache will always prioritize retaining the most recently used assets

Parameters:
Return type:

bool

property unreferenced_asset_storage_size_mb: float

[Read-Write] The asset cache will always retain all currently used assets. In addition to that, this limit specifies how much size is allocated to storing assets that remain only for the current session and that aren’t being used by any stage. Set this to 0 to disable storing unreferenced assets.

Type:

(double)