Is it possible to export to CPlane coordinates?
I don't think there is a way to do that easily.
Yes, not easily, but you can use RhinoScript. You will get an Origin, and 3 vectors for the x,y, z directions. You should post this to the Rhino Developer Newsgroup instead of this forum. There is a link to it here. The programming wizards are out there. Let them know why you want to do this, too!
Thanks for the links Mary. I'll check them out.