def __init__(self, geardata, flankmods=None):
        """
        Initialization of GearWheel-object
        Should be overwritten in derived classes

        INPUT parameter:
        geardata   : data of gear wheel (dictionary)
        flankmods  : data of flank modifications (dictionary)
        formcoords : list of 2d-coordinate points (list, list(len=2), numeric)
        """

        self.points_shaft = None
        self.data = deepcopy(geardata)
        self.modifications = deepcopy(flankmods)