diff --git a/a_opt_complete.json b/a_opt_complete.json
index a0f1083..c8ce885 100644
--- a/a_opt_complete.json
+++ b/a_opt_complete.json
@@ -259,7 +259,119 @@
                                         "description": "unknown.context.participations",
                                         "_class": "ObjectNode",
                                         "attributes": [
-                                            
+                                            {
+                                                "type": "C_SINGLE_ATTRIBUTE",
+                                                "rm_attribute_name": "function",
+                                                "children": [
+                                                    {
+                                                        "archetype_id": null,
+                                                        "path": "/context/participations/function",
+                                                        "type": "C_COMPLEX_OBJECT",
+                                                        "rm_type_name": "DV_TEXT",
+                                                        "node_id": null,
+                                                        "text": "Test all types.context.participations.function",
+                                                        "description": "unknown.context.participations.function",
+                                                        "_class": "ObjectNode",
+                                                        "attributes": [
+                                                            
+                                                        ]
+                                                    }
+                                                ]
+                                            },
+                                            {
+                                                "type": "C_SINGLE_ATTRIBUTE",
+                                                "rm_attribute_name": "mode",
+                                                "children": [
+                                                    {
+                                                        "archetype_id": null,
+                                                        "path": "/context/participations/mode",
+                                                        "type": "C_COMPLEX_OBJECT",
+                                                        "rm_type_name": "DV_CODED_TEXT",
+                                                        "node_id": null,
+                                                        "text": "Test all types.context.participations.mode",
+                                                        "description": "unknown.context.participations.mode",
+                                                        "_class": "ObjectNode",
+                                                        "attributes": [
+                                                            
+                                                        ]
+                                                    }
+                                                ]
+                                            },
+                                            {
+                                                "type": "C_SINGLE_ATTRIBUTE",
+                                                "rm_attribute_name": "time",
+                                                "children": [
+                                                    {
+                                                        "archetype_id": null,
+                                                        "path": "/context/participations/time",
+                                                        "type": "C_COMPLEX_OBJECT",
+                                                        "rm_type_name": "DV_INTERVAL<DV_DATE_TIME>",
+                                                        "node_id": null,
+                                                        "text": "Test all types.context.participations.time",
+                                                        "description": "unknown.context.participations.time",
+                                                        "_class": "ObjectNode",
+                                                        "attributes": [
+                                                            {
+                                                                "type": "C_SINGLE_ATTRIBUTE",
+                                                                "rm_attribute_name": "lower",
+                                                                "children": [
+                                                                    {
+                                                                        "archetype_id": null,
+                                                                        "path": "/context/participations/time/lower",
+                                                                        "type": "C_COMPLEX_OBJECT",
+                                                                        "rm_type_name": "DV_DATE_TIME",
+                                                                        "node_id": null,
+                                                                        "text": "Test all types.context.participations.time.lower",
+                                                                        "description": "unknown.context.participations.time.lower",
+                                                                        "_class": "ObjectNode",
+                                                                        "attributes": [
+                                                                            
+                                                                        ]
+                                                                    }
+                                                                ]
+                                                            },
+                                                            {
+                                                                "type": "C_SINGLE_ATTRIBUTE",
+                                                                "rm_attribute_name": "upper",
+                                                                "children": [
+                                                                    {
+                                                                        "archetype_id": null,
+                                                                        "path": "/context/participations/time/upper",
+                                                                        "type": "C_COMPLEX_OBJECT",
+                                                                        "rm_type_name": "DV_DATE_TIME",
+                                                                        "node_id": null,
+                                                                        "text": "Test all types.context.participations.time.upper",
+                                                                        "description": "unknown.context.participations.time.upper",
+                                                                        "_class": "ObjectNode",
+                                                                        "attributes": [
+                                                                            
+                                                                        ]
+                                                                    }
+                                                                ]
+                                                            }
+                                                        ]
+                                                    }
+                                                ]
+                                            },
+                                            {
+                                                "type": "C_SINGLE_ATTRIBUTE",
+                                                "rm_attribute_name": "performer",
+                                                "children": [
+                                                    {
+                                                        "archetype_id": null,
+                                                        "path": "/context/participations/performer",
+                                                        "type": "C_COMPLEX_OBJECT",
+                                                        "rm_type_name": "[PARTY_IDENTIFIED, PARTY_RELATED, PARTY_SELF]",
+                                                        "node_id": null,
+                                                        "text": "Test all types.context.participations.performer",
+                                                        "description": "unknown.context.participations.performer",
+                                                        "_class": "ObjectNode",
+                                                        "attributes": [
+                                                            
+                                                        ]
+                                                    }
+                                                ]
+                                            }
                                         ]
                                     }
                                 ]
diff --git a/src/main/groovy/com/cabolabs/openehr/opt/model/OperationalTemplate.groovy b/src/main/groovy/com/cabolabs/openehr/opt/model/OperationalTemplate.groovy
index da77a8b..48b149c 100644
--- a/src/main/groovy/com/cabolabs/openehr/opt/model/OperationalTemplate.groovy
+++ b/src/main/groovy/com/cabolabs/openehr/opt/model/OperationalTemplate.groovy
@@ -316,6 +316,7 @@ class OperationalTemplate {
          // for instance, a null_flavour could be in the OPT
          if (!obn.attributes.find{ it.rmAttributeName == attr })
          {
+            // TODO: support that type could be a list of possible types (inheritance structure only with concrete types), I guess here we should pick one or just add all the alternative types.
             if (Model.primitive_types.contains(type))
             {
                aom_type = 'C_PRIMITIVE_OBJECT'
@@ -332,6 +333,8 @@ class OperationalTemplate {
                obnc = new ObjectNode()
             }
 
+            println attr
+
             // avoid // on root paths
             path_sep = "/"
             if (obn.path == "/") path_sep = ""
diff --git a/src/main/groovy/com/cabolabs/openehr/rm_1_0_2/Model.groovy b/src/main/groovy/com/cabolabs/openehr/rm_1_0_2/Model.groovy
index 893c0d1..5dbd080 100644
--- a/src/main/groovy/com/cabolabs/openehr/rm_1_0_2/Model.groovy
+++ b/src/main/groovy/com/cabolabs/openehr/rm_1_0_2/Model.groovy
@@ -20,7 +20,7 @@ class Model {
          'location':       'String',
          'start_time':     'DV_DATE_TIME',
          'end_time':       'DV_DATE_TIME',
-         'participations': 'PARTICIPATION'
+         'participations': 'PARTICIPATION' // has many!
       ],
       'ACTION': [
          'time': 'DV_DATE_TIME',
@@ -84,6 +84,14 @@ class Model {
          'path': 'String'
       ],
 
+      'PARTICIPATION': [
+         function:  'DV_TEXT',
+         mode:      'DV_CODED_TEXT',
+         time:      'DV_INTERVAL<DV_DATE_TIME>',
+         // NOTE: in complete() the list in the type is not supported
+         performer: ['PARTY_IDENTIFIED', 'PARTY_RELATED', 'PARTY_SELF']
+      ],
+
       // DVs: this is for the DV_INTERVAL types here, to complete it's internal structs
       // NOTE: need to match specific type of DV_INTERVAL
       'DV_INTERVAL<DV_DATE>': [