Vector ====== Create a vector using an existing reference frame and specified distances. **Keyword Arguments** :param str name: Key to be used when referencing this vector in the mechanism.vectors dictionary. :param str ref_point_key: Key of the point used to mark the start of the vector. :param str ref_frame_key: Key of the frame in which the x, y, z components are measured. :param str x: Key of the parameter or generalized coordinate for distance in x- component of the reference frame. :param str y: Key of the parameter or generalized coordinate for distance in y- component of the reference frame. :param str z: Key of the parameter or generalized coordinate for distance in z- component of the reference frame.