diff --git a/src/fe_engine/element_type_conversion.hh b/src/fe_engine/element_type_conversion.hh
index 1bd56c58f..7718c2b24 100644
--- a/src/fe_engine/element_type_conversion.hh
+++ b/src/fe_engine/element_type_conversion.hh
@@ -1,58 +1,63 @@
 /**
  * @file   element_type_conversion.hh
  *
  * @author Nicolas Richart <nicolas.richart@epfl.ch>
  *
  * @date creation: Fri Jun 18 2010
  * @date last modification: Tue Sep 29 2020
  *
  * @brief  conversion between different types
  *
  *
  * @section LICENSE
  *
  * Copyright (©) 2010-2021 EPFL (Ecole Polytechnique Fédérale de Lausanne)
  * Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
  *
  * Akantu is free software: you can redistribute it and/or modify it under the
  * terms of the GNU Lesser General Public License as published by the Free
  * Software Foundation, either version 3 of the License, or (at your option) any
  * later version.
  *
  * Akantu is distributed in the hope that it will be useful, but WITHOUT ANY
  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  * A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
  * details.
  *
  * You should have received a copy of the GNU Lesser General Public License
  * along with Akantu. If not, see <http://www.gnu.org/licenses/>.
  *
  */
 
 /* -------------------------------------------------------------------------- */
 #include "element_class.hh"
 /* -------------------------------------------------------------------------- */
 
 #ifndef AKANTU_ELEMENT_TYPE_CONVERSION_HH_
 #define AKANTU_ELEMENT_TYPE_CONVERSION_HH_
 
 namespace akantu {
 
 template <class InType, class OutType> OutType convertType(InType /*unused*/) {
   return OutType();
 }
 
+template <>
+inline ElementType convertType<ElementType, ElementType>(ElementType type) {
+  return type;
+}
+
 template <>
 inline InterpolationType
 convertType<ElementType, InterpolationType>(ElementType type) {
   InterpolationType itp_type = _itp_not_defined;
 #define GET_ITP(type) itp_type = ElementClassProperty<type>::interpolation_type;
 
   AKANTU_BOOST_ALL_ELEMENT_SWITCH(GET_ITP);
 #undef GET_ITP
   return itp_type;
 }
 
 } // namespace akantu
 
 #endif /* AKANTU_ELEMENT_TYPE_CONVERSION_HH_ */