diff --git a/src/main/java/avatartranslator/AvatarDataTypePrimitiveFields.java b/src/main/java/avatartranslator/AvatarDataTypePrimitiveFields.java
index dba7805d078817b6742f55fc452794a93f131720..ca69b9aa176d8f4f2f673d72e95f1e15aa640f27 100644
--- a/src/main/java/avatartranslator/AvatarDataTypePrimitiveFields.java
+++ b/src/main/java/avatartranslator/AvatarDataTypePrimitiveFields.java
@@ -116,6 +116,11 @@ public class AvatarDataTypePrimitiveFields {
         }
         map.put(dt, primitiveFields);
     }
+
+    /**  unroll the nested datatype among the one provided as input to build the lists of primitive fields associated
+      * to each datatype.
+      * The returned result is a map that links each datatype with its primitive fields extension.
+      */
     public static HashMap<AvatarDataType, AvatarDataTypePrimitiveFields> buildMap(List<AvatarDataType> dtList, List<String> err) {
         HashMap<AvatarDataType, AvatarDataTypePrimitiveFields> map = new HashMap<AvatarDataType, AvatarDataTypePrimitiveFields>();
         for(AvatarDataType dt : dtList) buildPrimitiveFields(dt, map, new ArrayList<AvatarAttribute>(), err);