I had to make sure I was doing it correctly and I was – why is Orient3pt canceling out after I define my three reference points on the selected object? It won’t even ask me for the corresponding target points. The funny thing is however, if I define a reference point elsewhere (off of the selected object) it then asks me for the target points, but that is not what I want to do. Very weird.
The correct way (that isn’t working for me unfortunately): http://docs.mcneel.com/rhino/5/help/en-us/commands/orient3pt.htm
Thanks for your help OSX Rhino Forum!