+ Real len_in_halfspaces;
+ SCM user_set_len_scm = me->get_property_data ("length");
+ if (scm_is_number (user_set_len_scm))
+ len_in_halfspaces = scm_to_double (user_set_len_scm);
+ else
+ len_in_halfspaces = scm_to_double (calc_length (smob));
+ Real len = len_in_halfspaces * ss / 2;