def type1_transition(sheet, manager, **kwargs):
    """Custom type 1 transition event that tests if
    the the shorter edge of the face is smaller than
    the critical length.
    """
    type1_transition_spec = default_type1_transition_spec
    type1_transition_spec.update(**kwargs)
    face = type1_transition_spec["face"]

    edges = sheet.edge_df[sheet.edge_df["face"] == face]
    if min(edges["length"]) < type1_transition_spec["critical_length"]:
        exchange(sheet, face, type1_transition_spec["geom"])