It’s really very desirable to have a visualisation tool for multiple inheritance that can lay out the class hierarchy as a Haase diagram for when the size of the inheritance graph gets very large. The Seshat ontology is a good example of where it gets fairly difficult to manage without visualisation tools.
It is possible to load schemata from Protege into TerminusDB provided that the OWL is sufficiently simple. We don’t support all of OWL 2, particularly we don’t yet have support for equivalence.
Previously we had a schema builder within TerminusDB, but due to architectural changes required to bring out the collaboration features we had to rip it out for the time being. We’re planning to bring it back as soon as we can feasibly do so. I think it’s a few months down the line in our road map.
Currently the best way to build a complex schema is actually in WOQL. It tends to be a lot less verbose than writing it directly in OWL, especially when cardinalities are used.