def strip_idmeta(blockobj):
    """Return a list of (x, y, z) and drop the id_meta for blockobj"""
    if blockobj is not None:
        if type(blockobj) is dict:
            return list(pos for (pos, id_meta) in blockobj.items())
        else:
            return list(pos for (pos, id_meta) in blockobj)
    else:
        return None