When we compute dudeDuplications from a MooseModel, the mooseModel variable of the DudeSourceCodeFragments generated is never initialized with this MooseModel. When you send 'mooseModel' to any DudeSourceCodeFragment of the model, it resturns nil I guess any MooseEntity should store the mooseModel from which it was generated ? I opened an issue: http://code.google.com/p/moose-technology/issues/detail?id=462