virtual void RegisterISMDescriptors ( [AInstancedPlacementPartitionActor](API\Runtime\Engine\Instances\AInstancedPlacementPartitionActo-) * ParentPartitionActor, [TSortedMap](API\Runtime\Core\Containers\TSortedMap)< int32, [TArray](API\Runtime\Core\Containers\TArray)< FTransform >> & ISMDefinition ) const