Jul 14, 2021 · Jul 20, 2021 · Jul 22, 2021 · Jul 22, 2021 · Jul 22, 2021
diff --git a/lib/mpl_toolkits/mplot3d/art3d.py b/lib/mpl_toolkits/mplot3d/art3d.py
        self._sort_zpos = None
        self.stale = True

    def _zsortval(self, zs):
        """
        Compute the value to use for z-sorting given the viewer z
        coordinates of an object `zs`, with larger values drawn underneath
        smaller values.

        This function should never return `nan`, and returns `np.inf` if no
        non-nan value is computable.
        """
        nans = np.isnan(zs)
        return np.inf if nans.all() else self._zsortfunc(zs[~nans])

    def get_vector(self, segments3d):
        """Optimize points for projection."""
        if len(segments3d):
        if xyzlist:
            # sort by depth (furthest drawn first)
            z_segments_2d = sorted(
                ((self._zsortfunc(zs), np.column_stack([xs, ys]), fc, ec, idx)
                ((self._zsortval(zs), np.column_stack([xs, ys]), fc, ec, idx)
                 for idx, ((xs, ys, zs), fc, ec)
                 in enumerate(zip(xyzlist, cface, cedge))),
                key=lambda x: x[0], reverse=True)