def remove_bottom(pnts, gt_box, bottom):
    """
    Args:
        * `pnts`: Lidar Points
        * `gt_box`: The 3D bounding box of the object
        * `bottom`: A height threshold, deciding which points to keep\n
    Return:
        `pnts` whose heights are larger than -dz/2 + bottom, where dz is from the `gt_box`.
    """
    if bottom == 0.0:
        return pnts
    zthresh = -gt_box[5] / 2 + bottom
    keep_bool = pnts[:, 2] > zthresh
    return pnts[keep_bool]