The idea is export Pro/E and other CAD drawings to IsoDraw, from which isometric and 2D technical drawings are created. Links between the two mean that when the CAD drawing is changed, the illustration updates automatically.
Some might ask, "Why bother converting to 2D illustrations? Output the CAD drawing in 3D to PDF, instead." The problem with 3D PDF is that it is painfully slow. Viewing a page electronically shouldn't take longer than flipping a page in a paper book.