def line_2d_to_3d(line, zs=0, zdir=u'z'):
 line.__class__ = Line3D
 line.set_3d_properties(zs, zdir)

def line_2d_to_3d ( line , zs = 0 , zdir = u'z' ) : line . __class__ = Line3D line . set_3d_properties ( zs , zdir )
convert a 2d line to 3d .