def wpcsys(self, wn="", kcn="", **kwargs):
    """Defines the working plane location based on a coordinate system.

    APDL Command: WPCSYS

    Parameters
    ----------
    wn
        Window number whose viewing direction will be modified to be normal
        to the working plane (defaults to 1).  If WN is a negative value,
        the viewing direction will not be modified.

    kcn
        Coordinate system number.  KCN may be 0,1,2 or any previously
        defined local coordinate system number (defaults to the active
        system).

    Notes
    -----
    Defines a working plane location and orientation based on an existing
    coordinate system.  If a Cartesian system is used as the basis (KCN)
    for the working plane, the working plane will also be Cartesian, in the
    X-Y plane of the base system.  If a cylindrical, spherical, or toroidal
    base system is used, the working plane will be a polar system in the
    R-θ plane of the base system.

    If working plane tracking has been activated (CSYS,WP or CSYS,4), the
    updated active coordinate system will be of a similar type, except that
    a toroidal system will be updated to a cylindrical system.  See the
    Modeling and Meshing Guide for more information on working plane
    tracking.

    This command is valid in any processor.

    Some primitive generation commands will not honor R-theta
    transformations for non-cartesian coordinate systems. Refer to the
    primitive commands table for more information.
    """
    command = f"WPCSYS,{wn},{kcn}"
    return self.run(command, **kwargs)