Hello @d_keith,

thank you for reaching out to us and your extensive documentation efforts. Much appreciated! What you did there is correct, but in the spirit of simplicity, I think the code could be a bit condensed. There snuck in a few unused (and unrelated) includes and being so generous with separating things into help functions can impact readability and execution times. I also added the "expand asset category into sub-categories" thing you wanted.

In short: I think this is a good occasion to use a receiver callback function, as this structures the code naturally. Find my take below.

Cheers,
Ferdinand

The result:

categoryIds = [maxon.Id('category@b9c32d04a12d449ca1c758ddb3c695b0'), maxon.Id('category@985a9913c47341e4a373ca71d8e73b18')] name = 'Cloudy - VHDRI.hdr', asset.GetId() = 'file_e02d0a81b02be4fa' name = 'Default HDR.hdr', asset.GetId() = 'file_2792c7829905f40d' name = 'Desert.exr', asset.GetId() = 'file_0b3eb8e7595c1b5d' name = 'jhdri-v1_ext_sunset_seastar_acescg.exr', asset.GetId() = 'file_dc156adf0cc146e8' name = 'HDR012.hdr', asset.GetId() = 'file_b1db2c38badb130c'

The code:

"""Retrieves all MediaImage assets that are attached to the "Textures/HDR" category or one of its child categories. This is an application of what I dubbed "Filtered Asset searches" in the C++ Docs, find the Python example here [1]. References: [1] https://github.com/PluginCafe/cinema4d_py_sdk_extended/blob/master/scripts/05_modules/assets/asset_databases_r26.py#L416 """ import typing import maxon def ExpandAssetCategoryId(repo: maxon.AssetRepositoryInterface, cid: maxon.Id) -> list[maxon.Id]: """Retrieves the IDs of all descendant asset categories of #cid. """ # Get all asset category assets in #repo. categoryAssets: maxon.AssetDescription = repo.FindAssets( maxon.AssetTypes.Category(), maxon.Id(),maxon.Id(), maxon.ASSET_FIND_MODE.LATEST) # The IDs we have currently to check for descendants and the final result list. idsToCheck: list[maxon.Id] = [cid] results: list[maxon.Id] = [] # Try to empty #idsToCheck while popping elements from it and adding new ones. while idsToCheck: # Remove the first element and add it to the results. cid: maxon.Id = idsToCheck.pop() results.append(cid) # Find all category assets which have #cid as their parent category and add their IDs as # to be resolved category IDs. We stop the search here early, i.e., we assume the category # tree to be mono-hierarchical (one category can only be attached to one category). There # is not really anything in the Asset API which would enforce this, but it is how asset # categories are currently handled. for asset in categoryAssets: if cid == maxon.CategoryAssetInterface.GetParentCategory(asset): aid: typing.Any = asset.GetId() idsToCheck.append(aid if isinstance(aid, maxon.Id) else maxon.Id(aid)) break return results def main() -> None : """Runs the example. """ # Make sure the asset databases have been loaded and get the user repository, i.e., the # repository where more or less all content can be found. if not maxon.AssetDataBasesInterface.WaitForDatabaseLoading(): raise RuntimeError("Could not load asset databases.") repo: maxon.AssetRepositoryRef = maxon.AssetInterface.GetUserPrefsRepository() if not repo: raise RuntimeError("Unable to retrieve user repository.") # The final #results list where we put all the asset descriptions of image assets which are # parented to category assets with any of the IDs in #categoryIds. results: list[tuple[str, maxon.AssetDescription]] = [] # The root category we are interested in, this is the id for the "Textures/HDR" category. rootCategoryId: maxon.Id = maxon.Id("category@b9c32d04a12d449ca1c758ddb3c695b0") # Expand #rootCategoryId into a list of all its attached child categories. categoryIds: list[maxon.Id] = ExpandAssetCategoryId(repo, rootCategoryId) # The language Cinema 4D is running in, use GetDefaultLanguage() to evaluate things in engUS. currentLanguage: maxon.LanguageRef = maxon.Resource.GetCurrentLanguage() def onSearchHit(asset: maxon.AssetDescription) -> bool: """Called for each asset by the FindAssets() call below. Assets which match the search criteria are written to #results. """ # Get the metadata of the asset and assert that its subtype is MediaImage, step over an asset # when these operations fail. metadata: maxon.AssetMetaData = asset.GetMetaData() if metadata is None: return True sid: maxon.InternedId = maxon.InternedId(metadata.Get(maxon.ASSETMETADATA.SubType, maxon.Id())) if sid != maxon.ASSETMETADATA.SubType_ENUM_MediaImage: return True # Append the name of the asset and the asset itself to the results when #asset is parented # to a category asset with an ID which is contained ins #categoryIds. if maxon.CategoryAssetInterface.GetParentCategory(asset) in categoryIds: results.append((asset.GetMetaString(maxon.OBJECT.BASE.NAME, currentLanguage, ""), asset)) return True # Search #repo for all file type assets (this includes MediaImage assets) with any id and pass # the data through onSearchHit. repo.FindAssets( assetType=maxon.AssetTypes.File(), aid=maxon.Id(), version=maxon.Id(), findMode=maxon.ASSET_FIND_MODE.LATEST, receiver=onSearchHit) # Print the expanded category IDs and the first five asset matches associated with them. print (f"{categoryIds = }") for name, asset in results[:5]: print (f"{name = }, {asset.GetId() = }") if __name__ == "__main__": main()

Multiple end nodes of custom node space