Hi Friends, I have a boost::shared_ptr that stores a pointer to a base class ( class B1 ) and derived classes ( class D1 , class D2 ) both inheriting from the same Base class. The Constructors I have another set of factory classes ( base class : class base1, derived class : class derv1 & class derv2 ) whoose constructors accepts boost::shared_ptr of B1. When constructing derv1: I would like to cast pointer as D1 and ,when constructing derv2 : cast pointer as D2, but the only way I can access the class functions is through a shared_ptr to B1. My question is how do I cast B1 to get D1 and D2 in the constructors for derv1 and derv2 respectively ? the pseudo code is base1* createBase( boost::shared_ptr<B1> b_ptr , int type ) { if( type == 1 ) return new derv1( boost::polymorphic_downcast<AAAA> b_ptr ); else return new derv2( boost::polymorphic_downcast<XXXX> b_ptr ); } what do i write in the place of AAAA & XXXX for the code to wrk ?? Sorry for the long question, but could not express it in any shorter way.. thanks for ur patience and replies Dhanvi