std::vector< int > faceGroupIds = _faceGroupsIds[it-_faceGroupNames.begin()];
faceGroupIds.insert( faceGroupIds.end(), faceIds.begin(), faceIds.end());
/* Detect and erase duplicates face ids */
std::vector< int > faceGroupIds = _faceGroupsIds[it-_faceGroupNames.begin()];
faceGroupIds.insert( faceGroupIds.end(), faceIds.begin(), faceIds.end());
/* Detect and erase duplicates face ids */