Hi, I have a problem with serializing a derived classes through a pointer to a base class. I tried registering with the syntax from the documentation: |ar.template register_type(); | , which works well in case the derived class has a default constructor (just like the example). I just don't know what the syntax is for the case where the derived class does not have a default constructor (if I use the same syntax to register the derived class then I get a compilation error about the fact that there is no. I can provide an example in case this is not clear enough. Or, is it an absolute requirement for all derived classes to have a default constructor? Thank you and best regards, Dante