Open Sim is a open source for Second life. I am teaching Electrical Machinery in my university. This is hard to teach because it needs understanding both for mechanic and electrical mechanism.
I asked for senior graduate project as a Open Sim electrical machine virtual space development. The students managed to install and develop it. Even though they failed to integrate it with Moodle, it looks great! Take a look at the result. Sorry the contents are recorded using google casting and Korean voice.