Node unique identifiers?

HOOPS Exchange
1

Is there a system that assigns a unique identifier to each A3DTreeNode node in a A3DTree?

Not all nodes have names. Moreover, when converting a file to xml using the ImportExport example, I see the following on the XML:

<UserData Title="UNIQUE_ID">
				<UserValue Type="String" Value="1a117b7e-495e-4e39-8c5b-3a2cfe43c0ab-00057ac2" />
			</UserData>

So it seems that at some point the exchanger creates unique ids for the exported data. I would like to get these identifiers from the nodes.

I also see an ID on the ProductOccurrence:

        <ProductOccurrence pointer="0x63fd04a51940" Id="16" Name="Door-Curtain-Wall-Single-Glass" Layer="65535" Style="65535" Behaviour="1" Children="17" ModellerType="50" ProductLoadStatus="0" ProductFlag="2" Unit="304.80000000000001" DensityVolumeUnit="1" DensityMassUnit="1" UnitFromCAD="1" RGB="0.753 0.753 0.753">
			<Transformation RelativeTransfo="1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1" />
			<A3DMiscMaterialPropertiesData m_dDensity="-1" />
		</ProductOccurrence>

Does that correspond to one of the fields in here ? A3DRootBaseData — HOOPS Exchange Documentation

Or where does it come from?

2

Hello @camilo.talero,
Do you mean get the persistent ID from the tree node? If yes, you can refer to the HOOPS Exchange sample MeshViewer. In exchange.cpp, you can look for line 218, xml_entity.append_attribute("persistentUId") = root_data.m_uiPersistentId;

Best Regards,
Man

3

Thanks Man.

Our goal here is to get our hands on a UID that we can persist on a client, and use later to query the CAD file on a server. There appear to be ways to traverse the hierarchy in the PRC intermediate representation in memory, but I don’t see a way to get a serializable handle to a node in the hierarchy for O(1) lookups.

persistentUId sounds like what we are looking for, are there any docs or examples that show how to use that UID to query the CAD data once you have this UID?

4

Hello @aevyrie,
In the HOOPS Exchange documentation, there is a dedicated page for persistent IDs Persistent IDs — HOOPS Exchange Documentation.
Also, I found a discussion in forum - How to generate GUID to each node during conversion?.
If you have any further questions, please let me know. Thank you.

Best Regards,
Man