Hi @ghildebrand ,
Yes, we have published guidance and a code sample on converting OWL/RDF (serialized as TTL files) to DTDL.
Article - https://learn.microsoft.com/en-us/azure/digital-twins/how-to-integrate-models
Code Sample - https://learn.microsoft.com/en-us/samples/azure-samples/rdftodtdlconverter/digital-twins-model-conversion-samples/
Best,
Kevin