| On this page |
The PDG Asset Link allows you to cook and impor results from PDG Graphs embedded in HDAs directly in Unreal.
Creation ¶
The PDG Asset Link is automatically created after instantiating an HDA that contains a TOP Network.
It displays a list of the TOP Networks available in the HDA and the TOP Nodes available in the currently selected TOP Network. This also displays the options to cook, cancel, dirty all, and unload all work item objects.
Filters ¶
The PDG asset link uses a filter that specifies a prefix for the node names to avoid showing every TOP network node. This controls if they list in the Asset Link UI.
The default value for this filter is HE_, so only these are listed in the PDG Asset Link. For example HE_Terrain or HE_Trees.
The TOP output filter is another prefix filter to identify nodes that produce ouput BGEOs.
By default, the filter is set to HE_OUT_, so only these are load these work item output files. For example HE_OUT_Trees, HE_OUT_Roads, or HE_OUT_Buildings.
Those filters can be modified or disabled in the PDG Asset Link UI.
Loading Work Item Results ¶
When you cook the PDG Graph, it imports Work Items geometry output files (bgeos) that have successfully cooked on the TOP Output Nodes. The results are loaded on actors that reproduce the PDG Graph’s hierarchy:
-
TOP NETWORK
-
TOP NODE
-
WorkItemOutput1
-
WorkItemOutput2
-
WorkItemOutput3
-
-
Cooked PDG results are considered temporary like normal HDA outputs. Until baked, it’s owned by the Houdini Asset Actor. This means if you dirty or change the PDG assset, it can potentialy destroy or update them.
The PDG Asset Link has its own bake section, which allows for fine grain controls to decide how the PDG graph’s results are baked.
You can choose to bake all outputs, only the selected top network, or selected TOP node.
You can decide if you want to replace existing assets and actors created from a previous bake or create new ones.
Asynchronous Importer ¶
The PDG Asset Link allows you to use an asynchronous importer commandlet to import Work Item outputs once they are ready. This reduce lock ups of Unreal and is useful when processing lots of large meshes.
Asynchronous import can be enabled/started/stopped in the Work Item Import Settings entry in the Houdini Engine menu. The PDG Asset Link displays the status of the async importer in its details UI when in use.
Once started, the commandlet automatically imports the BGEO files from output work items, creating their UAssets.
After a successful import, the commandlet notifies the PDG asset link which then initiates the Uasset in the level.