As of Vectorworks 2015, there are a number of changes that allow you to create faster and smaller PDFs. A large number of improvements were implemented in the background that will make PDFs exported from Vectorworks 2015 smaller and lighter than those exported from previous versions, however, there are also settings that give you more direct control over this:
For PDFs already imported into a Vectorworks document, you will see an option in the Object info Palette for "Snap to Geometry":
If this option is checked, when you export your Vectorworks file as a PDF, the snapping geometry will be included for this PDF as well. This will allow the snapping information to be retained, but will also increase the size of the exported PDF as well as the Vectorworks file it resides in. Disabling this option before exporting to PDF will reduce the size of the exported PDF and the Vectorworks document, but the PDF within the Vectorworks file will export simply as an image.
Edited by JimW