It depends. Yes, normally.
This is a great example. It does work on OS X, with zero code changes. Here, give it a try…ExplodedView.macrhi (12.4 KB) - UPDATED on 11/4/2015
How much additional knowledge? That depends on the scope of the plugin. In the case of ExplodedView, very little additional knowledge was necessary to get it to work in Rhino for Mac. All the necessary information to do that is here. The important part to note is that David did not have to make any changes to his code…as long as he is writing using C# and making calls with RhinoCommon, getting it to work on Mac is trivial.
It can always be easier I guess I don’t understand this question, because it does work. If you’d like to know how, start here.
Stepping back a little…David says:
At the moment, you do have to compile two versions, but they are essentially the same. (We’re currently working on some approaches that could make it easier to “just use the same binary.”) That said, the amount of work needed to compile on each platform is very small…and there are many good reasons that you should compile on each platform anyway.