There’s a Blender add-on which is “really buggy” according to the author, and it tries to reimplement direct conversion of model data into Urho3D formats.
Why is there no Blender add-on simply delegating exports to the AssetImporter tool, calling it with the right parameters?
Even while this creates a dependency on the tool, this might be an advantage to have the same code doing the same stuff.
If anyone is interested, I can write it, having written several Blender add-ons in the past. I’d probably do that sooner or later because it speeds up the workflow a lot for me.