joining objects problem

Hello all,

I have a detailed model of a Toyota truck that is made from many different objects. I am able to select all of them and use ctrl+j to join them into one object. However when I export and then import (FILE type 3ds) it seems the join is not being saved. I need to reduce this model to a single list of vertices and edges for a program I am using that cannot handle groups in an object, does anyone know how to do this?

Thank you!