def find_pc_files(pc_tiles, pc_dir, pc_file_name, pc_tile_case):
    """Find pointcloud files in the file system when given a list of pointcloud tile names
    """
    # Prepare AHN file names -------------------------------------------------
    if pc_tile_case == "upper":
        tiles = [pc_file_name.format(tile=t.upper()) for t in pc_tiles]
    elif pc_tile_case == "lower":
        tiles = [pc_file_name.format(tile=t.lower()) for t in pc_tiles]
    elif pc_tile_case == "mixed":
        tiles = [pc_file_name.format(tile=t) for t in pc_tiles]
    else:
        raise "Please provide one of the allowed values for pc_tile_case."
    # use the tile list in tiles to parse the pointcloud file names
    pc_path = [os.path.join(pc_dir, pc_tile) for pc_tile in tiles]

    if all([os.path.isfile(p) for p in pc_path]):
        return(pc_path)
    else:
        return(None)