BB, If I'm understanding you correctly on what your parametric geometry is, you have created a script that enables you to make geometry according to a set of input parameters, but also what some programs would refer to as with a history stack.
So, you can create your objects and input any setting you want as you are creating, and even after it's created you can still adjust the parameters, allowing you to create various resolutions and various shapes such as pupil dilation.

What happens when you export it as OBJ and bring it back into Poser? Can your script adjust parameters on what has become a static OBJ file without a history? Or is it forever locked within Poser as a .py file and subject to the user needing to have the script?

That's what I meant by morphing the pupil - without the script and the unique Poser object, it's only good old regular 3D geometry that needs to be dealt with as a regular 3D mesh.

Unless I'm misunderstanding it, it sounds to me like something only for Poser and only exists as it is with its unique properties as long as it remains in Poser. The problem with that, of course, is many many people use other apps for rendering.

Bottom line is, I assumed you took all this into account and had an actual *.obj file made and ready to be dealt with in traditional ways.