I read the forums however they all seem to be based on a users input of another field(s). I want the field to be calculated on PDFOpen date....and hoping I don't need hidden form fields to achieve it. Thanks though, I'll keep looking.
But the date you're calculating from is located in a field, no? Then it's exactly the same as the age calculation situations. You just trigger it from a doc-level script, instead of from a field.