@spiceErrorCheck<EOL>def pl2nvc(plane):
assert (isinstance(plane, stypes.Plane))<EOL>normal = stypes.emptyDoubleVector(<NUM_LIT:3>)<EOL>constant = ctypes.c_double()<EOL>libspice.pl2nvc_c(ctypes.byref(plane), normal, ctypes.byref(constant))<EOL>return stypes.cVectorToPython(normal), constant.value<EOL>
Return a unit normal vector and constant that define a specified plane.

http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/pl2nvc_c.html

:param plane: A SPICE plane.
:type plane: supporttypes.Plane
:return:
        A normal vector and constant defining
        the geometric plane represented by plane.
:rtype: tuple