Question about deriving custom entities

[Jon Rizzo]

I have been using ObjectARX for about 6 months - but only to define
commands. I have gone through the lab exercises, and am now making my
first attempt at a custom entity.

This is what I have done:
To get me started quickly, I used the ObjectARX wizard. I derrived a
custom class from AcDbPolyline. I used the ObjectARX class wizard to
implement the functions that are necessary (worldDraw, dwgInFields,
etc.), but I didn't make any changes to the wizard generated code.

My question is this: since I didn't add/change any functionality of
the base class, shouldn't I be able to create an instance of my object
type and append it to the database as if it were an AcDbPolyline? I
tried this, and all of the function calls worked properly, but nothing
was added to the database.

Would it be easier to derrive from AcDbEntity and declare an
AcDbPolyline as a data member? That seems a bit clunky.

Jon