Generating UML from the ontology

Is there a way to generate a UML diagram. Essentially, I used an SQL ORM lately and having the capability of generating a UML diagram of reality was really great. That got me thinking this would be a great feature if Stardog Studio or other would support this.

Depending on your ontology (ignore me if you know this already, and yours will be fine), a mapping to UML won't typically be feasible in a useful way. If you have Sparx Enterprise Architect available to you (I think they have a 30 day trial), you can load an RDF file into that and it will generate UML as best it can.