def bar3d(self, x, y, z, dx, dy, dz, color=None,
          zsort='average', shade = True, *args, **kwargs):
    '''
    Generate a 3D bar, or multiple bars.

    When generating multiple bars, x, y, z have to be arrays.
    dx, dy, dz can be arrays or scalars.

    *color* can be:

     - A single color value, to color all bars the same color.

     - An array of colors of length N bars, to color each bar
       independently.

     - An array of colors of length 6, to color the faces of the
       bars similarly.

     - An array of colors of length 6 * N bars, to color each face
       independently.

     When coloring the faces of the boxes specifically, this is
     the order of the coloring:

      1. -Z (bottom of box)
      2. +Z (top of box)
      3. -Y
      4. +Y
      5. -X
      6. +X

    Keyword arguments are passed onto
    :func:`~mpl_toolkits.mplot3d.art3d.Poly3DCollection`
    '''
    had_data = self.has_data()

    if not cbook.iterable(x):
        x = [x]
    if not cbook.iterable(y):
        y = [y]
    if not cbook.iterable(z):
        z = [z]

    if not cbook.iterable(dx):
        dx = [dx]
    if not cbook.iterable(dy):
        dy = [dy]
    if not cbook.iterable(dz):
        dz = [dz]

    if len(dx) == 1:
        dx = dx * len(x)
    if len(dy) == 1:
        dy = dy * len(y)
    if len(dz) == 1:
        dz = dz * len(z)

    if len(x) != len(y) or len(x) != len(z):
        warnings.warn('x, y, and z must be the same length.')

    # FIXME: This is archaic and could be done much better.
    minx, miny, minz = 1e20, 1e20, 1e20
    maxx, maxy, maxz = -1e20, -1e20, -1e20

    polys = []
    for xi, yi, zi, dxi, dyi, dzi in zip(x, y, z, dx, dy, dz):
        minx = min(xi, minx)
        maxx = max(xi + dxi, maxx)
        miny = min(yi, miny)
        maxy = max(yi + dyi, maxy)
        minz = min(zi, minz)
        maxz = max(zi + dzi, maxz)

        polys.extend([
            ((xi, yi, zi), (xi + dxi, yi, zi),
                (xi + dxi, yi + dyi, zi), (xi, yi + dyi, zi)),
            ((xi, yi, zi + dzi), (xi + dxi, yi, zi + dzi),
                (xi + dxi, yi + dyi, zi + dzi), (xi, yi + dyi, zi + dzi)),

            ((xi, yi, zi), (xi + dxi, yi, zi),
                (xi + dxi, yi, zi + dzi), (xi, yi, zi + dzi)),
            ((xi, yi + dyi, zi), (xi + dxi, yi + dyi, zi),
                (xi + dxi, yi + dyi, zi + dzi), (xi, yi + dyi, zi + dzi)),

            ((xi, yi, zi), (xi, yi + dyi, zi),
                (xi, yi + dyi, zi + dzi), (xi, yi, zi + dzi)),
            ((xi + dxi, yi, zi), (xi + dxi, yi + dyi, zi),
                (xi + dxi, yi + dyi, zi + dzi), (xi + dxi, yi, zi + dzi)),
        ])

    facecolors = []
    if color is None:
        color = [self._get_patches_for_fill.get_next_color()]

    if len(color) == len(x):
        # bar colors specified, need to expand to number of faces
        for c in color:
            facecolors.extend([c] * 6)
    else:
        # a single color specified, or face colors specified explicitly
        facecolors = list(mcolors.to_rgba_array(color))
        if len(facecolors) < len(x):
            facecolors *= (6 * len(x))

    normals = self._generate_normals(polys)
if shade:
	sfacecolors = self._shade_colors(facecolors, normals)
else:
	sfacecolors = facecolors
    col = art3d.Poly3DCollection(polys,
                                 zsort=zsort,
                                 facecolor=sfacecolors,
                                 *args, **kwargs)
    self.add_collection(col)

    self.auto_scale_xyz((minx, maxx), (miny, maxy), (minz, maxz), had_data)

    return col