diff --git a/locale/fr/LC_MESSAGES/rougail.po b/locale/fr/LC_MESSAGES/rougail.po
index 569f5168b..9d400540a 100644
--- a/locale/fr/LC_MESSAGES/rougail.po
+++ b/locale/fr/LC_MESSAGES/rougail.po
@@ -5,8 +5,8 @@
 msgid ""
 msgstr ""
 "Project-Id-Version: \n"
-"POT-Creation-Date: 2025-05-03 22:50+0200\n"
-"PO-Revision-Date: 2025-05-03 22:50+0200\n"
+"POT-Creation-Date: 2025-05-08 21:35+0200\n"
+"PO-Revision-Date: 2025-05-08 21:37+0200\n"
 "Last-Translator: \n"
 "Language-Team: \n"
 "Language: fr\n"
@@ -135,6 +135,12 @@ msgid ""
 msgstr ""
 "la variable \"{0}\" a la valeur par défaut invalide \"{1}\" devrait être {2}"
 
+#: src/rougail/config.py:226
+msgid "Structure format version by default, if not specified in structure file"
+msgstr ""
+"La version du format de la structure par défaut, si non spécifier dans le "
+"fichier de structure"
+
 #: src/rougail/config.py:234
 msgid "File with functions"
 msgstr "Fichier avec les fonctions"
@@ -193,39 +199,47 @@ msgstr "Le patron de secret pour construire le nom de l'élément dans Bitwarden
 msgid "The pattern is in Jinja format"
 msgstr "Le patron est au format Jinja"
 
-#: src/rougail/config.py:458
+#: src/rougail/config.py:378
+msgid "Select for {0}"
+msgstr "Sélection pour {0}"
+
+#: src/rougail/config.py:457
+msgid "Override default parameters for option type"
+msgstr "Sur charger les paramètre par défaut pour le type d'option"
+
+#: src/rougail/config.py:460
 msgid "Default parameters for option type"
 msgstr "Paramètre par défaut pour le type d'option"
 
-#: src/rougail/convert.py:281
+#: src/rougail/convert.py:280
 msgid "unknown type {0} for {1}"
 msgstr "type {0} inconnu pour {1}"
 
-#: src/rougail/convert.py:416
+#: src/rougail/convert.py:411
 msgid "family \"{0}\" define multiple time"
 msgstr "la famille \"{0}\" est définit plusieurs fois"
 
-#: src/rougail/convert.py:679
+#: src/rougail/convert.py:667
 msgid "variable \"{0}\" define multiple time"
 msgstr "la variable \"{0}\" est définit plusieurs fois"
 
-#: src/rougail/convert.py:782
+#: src/rougail/convert.py:767
 msgid "params must be a dict for {0}"
 msgstr "params doit être une dict pour {0}"
 
-#: src/rougail/convert.py:803
+#: src/rougail/convert.py:788
 msgid "\"{0}\" has an invalid \"params\" for {1}: {2}"
 msgstr "\"{0}\" a un attribut \"params\" invalide pour {1}: {2}"
 
-#: src/rougail/convert.py:817
+#: src/rougail/convert.py:802
 msgid "secret_manager must be a dict for {0}"
 msgstr "secret_manager doit être une dict pour {0}"
 
-#: src/rougail/convert.py:1147
+#: src/rougail/convert.py:1129
 msgid "Cannot execute annotate multiple time"
 msgstr "Ne peut exécuter l'annotation plusieurs fois"
 
-#: src/rougail/convert.py:1154
+#: src/rougail/convert.py:1136
 msgid ""
 "invalid \"structural\" definition ({0}), we cannot load any structural file!"
 msgstr ""
@@ -237,45 +251,45 @@ msgstr ""
 msgid "{0} in {1}"
 msgstr "{0} dans {1}"
 
-#: src/rougail/object_model.py:51
+#: src/rougail/object_model.py:50
 msgid "unknown boolean value \"{0}\""
 msgstr "valeur du booléen inconnue \"{0}\""
 
-#: src/rougail/object_model.py:182
+#: src/rougail/object_model.py:181
 msgid "cannot find variable \"{0}\" defined in attribute \"{1}\" for \"{2}\""
 msgstr ""
 "ne peut trouver la variable \"{0}\" défini dans l'attribut \"{1}\" pour "
 "\"{2}\""
 
-#: src/rougail/object_model.py:186
+#: src/rougail/object_model.py:185
 msgid ""
 "the variable \"{0}\" is in fact a family in attribute \"{1}\" for \"{2}\""
 msgstr ""
 "la variable \"{0}\" est en faite une famille dans l'attribut \"{1}\" pour "
 "\"{2}\""
 
-#: src/rougail/object_model.py:189 src/rougail/object_model.py:479
+#: src/rougail/object_model.py:188 src/rougail/object_model.py:478
 msgid "unknown object \"{0}\" in attribute \"{1}\" for \"{2}\""
 msgstr "objet inconnu \"{0}\" dans l'attribut \"{1}\" pour \"{2}\""
 
-#: src/rougail/object_model.py:206
+#: src/rougail/object_model.py:205
 msgid ""
 "identifier parameter for \"{0}\" in \"{1}\" cannot be set none dynamic family"
 msgstr ""
 "le paramètre identifier pour \"{0}\" dans \"{1}\" ne peut être placé pour "
 "une famille non dynamique"
 
-#: src/rougail/object_model.py:229
+#: src/rougail/object_model.py:228
 msgid "cannot find variable \"{0}\" defined in \"{1}\" for \"{2}\""
 msgstr "ne peut trouver la variable \"{0}\" défini dans \"{1}\" pour \"{2}\""
 
-#: src/rougail/object_model.py:232
+#: src/rougail/object_model.py:231
 msgid "variable \"{0}\" defined in \"{1}\" for \"{2}\" is a dynamic variable"
 msgstr ""
 "la variable \"{0}\" défini dans \"{1}\" pour \"{2}\" est une variable "
 "dynamique"
 
-#: src/rougail/object_model.py:243
+#: src/rougail/object_model.py:242
 msgid ""
 "the variable \"{0}\" is not a follower, so cannot have index type for param "
 "in \"{1}\""
@@ -283,7 +297,7 @@ msgstr ""
 "la variable \"{0}\" n'est pas suiveuse, donc ne peut avoir de type index "
 "comme paramètre dans \"{1}\""
 
-#: src/rougail/object_model.py:476
+#: src/rougail/object_model.py:475
 msgid ""
 "a variable \"{0}\" is needs in attribute \"{1}\" for \"{2}\" but it's a "
 "family"
@@ -291,7 +305,7 @@ msgstr ""
 "une variable \"{0}\" est nécessaire pour l'attribut \"{1}\" pour \"{2}\" "
 "mais c'est une famille"
 
-#: src/rougail/object_model.py:496
+#: src/rougail/object_model.py:495
 msgid ""
 "variable \"{0}\" has an attribute \"{1}\" calculated with the unknown "
 "variable \"{2}\""
@@ -299,7 +313,7 @@ msgstr ""
 "la variable \"{0}\" a un attribut invalide \"{1}\" calculé avec la variable "
 "inconnue \"{2}\""
 
-#: src/rougail/object_model.py:532
+#: src/rougail/object_model.py:531
 msgid ""
 "the variable \"{0}\" has an invalid \"{1}\" the variable \"{2}\" is in a sub "
 "dynamic option"
@@ -307,14 +321,14 @@ msgstr ""
 "la variable \"{0}\" a un attribut invalide \"{1}\", la variable \"{2}\" est "
 "dans une sous option dynamique"
 
-#: src/rougail/object_model.py:535
+#: src/rougail/object_model.py:534
 msgid ""
 "the leader \"{0}\" has an invalid \"{1}\" the follower \"{2}\" is a multi"
 msgstr ""
 "la variable meneuse \"{0}\" a un attribut invalide \"{1}\", la variable "
 "suiveuse \"{2}\" est multiple"
 
-#: src/rougail/object_model.py:551
+#: src/rougail/object_model.py:550
 msgid ""
 "the variable \"{0}\" has an invalid attribute \"{1}\", the variable \"{2}\" "
 "must not be multi"
@@ -322,7 +336,7 @@ msgstr ""
 "la variable \"{0}\" a un attribut invalide \"{1}\", la variable \"{2}\" ne "
 "doit pas être multiple"
 
-#: src/rougail/object_model.py:556
+#: src/rougail/object_model.py:555
 msgid ""
 "the variable \"{0}\" has an invalid attribute \"{1}\", the variable must not "
 "be a multi or the variable \"{2}\" must be multi"
@@ -330,7 +344,7 @@ msgstr ""
 "la variable \"{0}\" a un attribut invalide \"{1}\", la variable ne doit pas "
 "être multiple ou la variable \"{2}\" doit être multiple"
 
-#: src/rougail/object_model.py:561
+#: src/rougail/object_model.py:560
 msgid ""
 "the variable \"{0}\" has an invalid attribute \"{1}\", the variable must be "
 "a multi or the variable \"{2}\" must not be multi"
@@ -338,7 +352,7 @@ msgstr ""
 "la variable \"{0}\" a un attribut invalide \"{1}\", la variable doit être "
 "multiple ou la variable \"{2}\" ne doit pas être multiple"
 
-#: src/rougail/object_model.py:566
+#: src/rougail/object_model.py:565
 msgid ""
 "the variable \"{0}\" has an invalid attribute \"{1}\", the variable \"{2}\" "
 "is multi but is inside a list"
@@ -362,7 +376,7 @@ msgstr ""
 "la variable \"{0}\" a une valeur par défaut calculé a partir de \"{1}\" "
 "laquelle a un type incompatible"
 
-#: src/rougail/object_model.py:628
+#: src/rougail/object_model.py:629
 msgid ""
 "\"when\" is not allowed in format version 1.0 for attribute \"{0}\" for "
 "variable \"{1}\""
@@ -370,7 +384,7 @@ msgstr ""
 "\"when\" n'est pas autorisé avec le format en version 1.0 pour l'attribut "
 "\"{0}\" pour la variable \"{1}\""
 
-#: src/rougail/object_model.py:631
+#: src/rougail/object_model.py:632
 msgid ""
 "the variable \"{0}\" has an invalid attribute \"{1}\", \"when\" and "
 "\"when_not\" cannot set together"
@@ -378,7 +392,7 @@ msgstr ""
 "la variable \"{0}\" a un attribut invalide \"{1}\", \"when\" et \"when_not\" "
 "ne peuvent pas être défini ensemble"
 
-#: src/rougail/object_model.py:637
+#: src/rougail/object_model.py:638
 msgid ""
 "\"when_not\" is not allowed in format version 1.0 for attribute \"{0}\" for "
 "variable \"{1}\""
@@ -386,7 +400,7 @@ msgstr ""
 "\"when_not\" n'est pas autorisé au format 1.0 pour l'attribut \"{0}\" pour "
 "la variable variable \"{1}\""
 
-#: src/rougail/object_model.py:691
+#: src/rougail/object_model.py:693
 msgid ""
 "cannot find variable \"{0}\" for the information \"{1}\" when calculating "
 "\"{2}\""
@@ -394,18 +408,18 @@ msgstr ""
 "ne peut trouver la variable \"{0}\" pour l'information \"{1}\" lors du "
 "calcul de \"{2}\""
 
-#: src/rougail/object_model.py:694
+#: src/rougail/object_model.py:696
 msgid ""
 "identifier not allowed for the information \"{0}\" when calculating \"{1}\""
 msgstr ""
 "identifier n'est pas autorisé pour l'information \"{0}\" lors du calcul de "
 "\"{1}\""
 
-#: src/rougail/object_model.py:743
+#: src/rougail/object_model.py:747
 msgid "\"when\" is not allowed in format version 1.0 for attribute \"{0}\""
 msgstr "\"when\" n'est pas autorisé au format 1.0 pour l'attribut \"{0}\""
 
-#: src/rougail/object_model.py:747 src/rougail/object_model.py:755
+#: src/rougail/object_model.py:751 src/rougail/object_model.py:759
 msgid ""
 "the identifier has an invalid attribute \"{0}\", \"when\" and \"when_not\" "
 "cannot set together"
@@ -413,7 +427,7 @@ msgstr ""
 "l'identifiant a un attribut invalide \"{0}\", \"when\" et \"when_not\" ne "
 "peuvent pas être défini ensemble"
 
-#: src/rougail/object_model.py:777
+#: src/rougail/object_model.py:782
 msgid ""
 "the variable \"{0}\" is not a follower, so cannot have index type for \"{1}\""
 msgstr ""
diff --git a/locale/rougail.pot b/locale/rougail.pot
index a2624084d..74ce1ee1d 100644
--- a/locale/rougail.pot
+++ b/locale/rougail.pot
@@ -5,7 +5,7 @@
 msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
-"POT-Creation-Date: 2025-05-03 22:50+0200\n"
+"POT-Creation-Date: 2025-05-08 21:37+0200\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -87,6 +87,10 @@ msgstr ""
 msgid "the variable \"{0}\" has an unvalid default value \"{1}\" should be in {2}"
 msgstr ""
 
+#: src/rougail/config.py:226
+msgid "Structure format version by default, if not specified in structure file"
+msgstr ""
+
 #: src/rougail/config.py:234
 msgid "File with functions"
 msgstr ""
@@ -143,39 +147,47 @@ msgstr ""
 msgid "The pattern is in Jinja format"
 msgstr ""
 
-#: src/rougail/config.py:458
+#: src/rougail/config.py:378
+msgid "Select for {0}"
+msgstr ""
+
+#: src/rougail/config.py:457
+msgid "Override default parameters for option type"
+msgstr ""
+
+#: src/rougail/config.py:460
 msgid "Default parameters for option type"
 msgstr ""
 
-#: src/rougail/convert.py:281
+#: src/rougail/convert.py:280
 msgid "unknown type {0} for {1}"
 msgstr ""
 
-#: src/rougail/convert.py:416
+#: src/rougail/convert.py:411
 msgid "family \"{0}\" define multiple time"
 msgstr ""
 
-#: src/rougail/convert.py:679
+#: src/rougail/convert.py:667
 msgid "variable \"{0}\" define multiple time"
 msgstr ""
 
-#: src/rougail/convert.py:782
+#: src/rougail/convert.py:767
 msgid "params must be a dict for {0}"
 msgstr ""
 
-#: src/rougail/convert.py:803
+#: src/rougail/convert.py:788
 msgid "\"{0}\" has an invalid \"params\" for {1}: {2}"
 msgstr ""
 
-#: src/rougail/convert.py:817
+#: src/rougail/convert.py:802
 msgid "secret_manager must be a dict for {0}"
 msgstr ""
 
-#: src/rougail/convert.py:1147
+#: src/rougail/convert.py:1129
 msgid "Cannot execute annotate multiple time"
 msgstr ""
 
-#: src/rougail/convert.py:1154
+#: src/rougail/convert.py:1136
 msgid "invalid \"structural\" definition ({0}), we cannot load any structural file!"
 msgstr ""
 
@@ -184,67 +196,67 @@ msgstr ""
 msgid "{0} in {1}"
 msgstr ""
 
-#: src/rougail/object_model.py:51
+#: src/rougail/object_model.py:50
 msgid "unknown boolean value \"{0}\""
 msgstr ""
 
-#: src/rougail/object_model.py:182
+#: src/rougail/object_model.py:181
 msgid "cannot find variable \"{0}\" defined in attribute \"{1}\" for \"{2}\""
 msgstr ""
 
-#: src/rougail/object_model.py:186
+#: src/rougail/object_model.py:185
 msgid "the variable \"{0}\" is in fact a family in attribute \"{1}\" for \"{2}\""
 msgstr ""
 
-#: src/rougail/object_model.py:189 src/rougail/object_model.py:479
+#: src/rougail/object_model.py:188 src/rougail/object_model.py:478
 msgid "unknown object \"{0}\" in attribute \"{1}\" for \"{2}\""
 msgstr ""
 
-#: src/rougail/object_model.py:206
+#: src/rougail/object_model.py:205
 msgid "identifier parameter for \"{0}\" in \"{1}\" cannot be set none dynamic family"
 msgstr ""
 
-#: src/rougail/object_model.py:229
+#: src/rougail/object_model.py:228
 msgid "cannot find variable \"{0}\" defined in \"{1}\" for \"{2}\""
 msgstr ""
 
-#: src/rougail/object_model.py:232
+#: src/rougail/object_model.py:231
 msgid "variable \"{0}\" defined in \"{1}\" for \"{2}\" is a dynamic variable"
 msgstr ""
 
-#: src/rougail/object_model.py:243
+#: src/rougail/object_model.py:242
 msgid "the variable \"{0}\" is not a follower, so cannot have index type for param in \"{1}\""
 msgstr ""
 
-#: src/rougail/object_model.py:476
+#: src/rougail/object_model.py:475
 msgid "a variable \"{0}\" is needs in attribute \"{1}\" for \"{2}\" but it's a family"
 msgstr ""
 
-#: src/rougail/object_model.py:496
+#: src/rougail/object_model.py:495
 msgid "variable \"{0}\" has an attribute \"{1}\" calculated with the unknown variable \"{2}\""
 msgstr ""
 
-#: src/rougail/object_model.py:532
+#: src/rougail/object_model.py:531
 msgid "the variable \"{0}\" has an invalid \"{1}\" the variable \"{2}\" is in a sub dynamic option"
 msgstr ""
 
-#: src/rougail/object_model.py:535
+#: src/rougail/object_model.py:534
 msgid "the leader \"{0}\" has an invalid \"{1}\" the follower \"{2}\" is a multi"
 msgstr ""
 
-#: src/rougail/object_model.py:551
+#: src/rougail/object_model.py:550
 msgid "the variable \"{0}\" has an invalid attribute \"{1}\", the variable \"{2}\" must not be multi"
 msgstr ""
 
-#: src/rougail/object_model.py:556
+#: src/rougail/object_model.py:555
 msgid "the variable \"{0}\" has an invalid attribute \"{1}\", the variable must not be a multi or the variable \"{2}\" must be multi"
 msgstr ""
 
-#: src/rougail/object_model.py:561
+#: src/rougail/object_model.py:560
 msgid "the variable \"{0}\" has an invalid attribute \"{1}\", the variable must be a multi or the variable \"{2}\" must not be multi"
 msgstr ""
 
-#: src/rougail/object_model.py:566
+#: src/rougail/object_model.py:565
 msgid "the variable \"{0}\" has an invalid attribute \"{1}\", the variable \"{2}\" is multi but is inside a list"
 msgstr ""
 
@@ -256,35 +268,35 @@ msgstr ""
 msgid "variable \"{0}\" has a default value calculated with \"{1}\" which has incompatible type"
 msgstr ""
 
-#: src/rougail/object_model.py:628
+#: src/rougail/object_model.py:629
 msgid "\"when\" is not allowed in format version 1.0 for attribute \"{0}\" for variable \"{1}\""
 msgstr ""
 
-#: src/rougail/object_model.py:631
+#: src/rougail/object_model.py:632
 msgid "the variable \"{0}\" has an invalid attribute \"{1}\", \"when\" and \"when_not\" cannot set together"
 msgstr ""
 
-#: src/rougail/object_model.py:637
+#: src/rougail/object_model.py:638
 msgid "\"when_not\" is not allowed in format version 1.0 for attribute \"{0}\" for variable \"{1}\""
 msgstr ""
 
-#: src/rougail/object_model.py:691
+#: src/rougail/object_model.py:693
 msgid "cannot find variable \"{0}\" for the information \"{1}\" when calculating \"{2}\""
 msgstr ""
 
-#: src/rougail/object_model.py:694
+#: src/rougail/object_model.py:696
 msgid "identifier not allowed for the information \"{0}\" when calculating \"{1}\""
 msgstr ""
 
-#: src/rougail/object_model.py:743
+#: src/rougail/object_model.py:747
 msgid "\"when\" is not allowed in format version 1.0 for attribute \"{0}\""
 msgstr ""
 
-#: src/rougail/object_model.py:747 src/rougail/object_model.py:755
+#: src/rougail/object_model.py:751 src/rougail/object_model.py:759
 msgid "the identifier has an invalid attribute \"{0}\", \"when\" and \"when_not\" cannot set together"
 msgstr ""
 
-#: src/rougail/object_model.py:777
+#: src/rougail/object_model.py:782
 msgid "the variable \"{0}\" is not a follower, so cannot have index type for \"{1}\""
 msgstr ""
 
diff --git a/src/rougail/locale/fr/LC_MESSAGES/rougail.mo b/src/rougail/locale/fr/LC_MESSAGES/rougail.mo
index df373926c..571995390 100644
Binary files a/src/rougail/locale/fr/LC_MESSAGES/rougail.mo and b/src/rougail/locale/fr/LC_MESSAGES/rougail.mo differ
diff --git a/src/rougail/object_model.py b/src/rougail/object_model.py
index 3eb0715cd..063c46464 100644
--- a/src/rougail/object_model.py
+++ b/src/rougail/object_model.py
@@ -26,10 +26,9 @@ from pydantic import (
     StrictStr,
     ConfigDict,
 )
-from tiramisu import undefined
 import tiramisu
 from tiramisu.config import get_common_path
-from .utils import get_jinja_variable_to_param, calc_multi_for_type_variable
+from .utils import get_jinja_variable_to_param, calc_multi_for_type_variable, undefined
 from .i18n import _
 from .error import DictConsistencyError, VariableCalculationDependencyError
 
diff --git a/src/rougail/user_datas.py b/src/rougail/user_datas.py
index c38257baa..7df24661f 100644
--- a/src/rougail/user_datas.py
+++ b/src/rougail/user_datas.py
@@ -22,8 +22,8 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 from typing import List
 from re import findall
 
-from rougail.utils import normalize_family
-from tiramisu import undefined, Calculation
+from rougail.utils import normalize_family, undefined
+from tiramisu import Calculation
 from tiramisu.error import (
     PropertiesOptionError,
     LeadershipError,
diff --git a/src/rougail/utils.py b/src/rougail/utils.py
index ccc41e9d1..3db019afc 100644
--- a/src/rougail/utils.py
+++ b/src/rougail/utils.py
@@ -199,3 +199,10 @@ def calc_multi_for_type_variable(local_variable: 'Variable', variable_in_calcula
             elif count_identifiers > 1:
                 variable_in_calculation_multi = 'submulti'
     return local_variable_multi, variable_in_calculation_multi
+
+
+class Undefined:
+    pass
+
+
+undefined = Undefined()