Hi! I’ve found that exporting as an x3d and vrml is supposed to be supported, but I don’t see this option in the list when I go to export. Thoughts? (http://docs.mcneel.com/rhino/5/help/en-us/fileio/x3d_x3dv_export.htm)
The web page you reference is for Windows Rhino. Rhino for Mac is still in development and neither of these file exporters are implemented on the Mac.