In VectorWorks 2008 there is a new export command that will export your 3D model…
Reasons To Be Cheerful Part 4 (upgrading to 2008) Import and Export AutoCAD 2007/08
I’ve had a few phone calls lately from clients. They have received an AutoCAD drawing from the engineer or architect and they can’t import it into VectorWorks. They are upset and confused, because in the past they were able in import these drawings from the consultant.
The answer is that the consultant has updated AutoCAD and now VectorWorks is not able to open the new DWG format.
It’s not all lost. VectorWorks 2008 is now able to import and export AutoCAD 2007/08 files.
So, if you are having trouble with importing and exporting new AutoCAD files your answer is to upgrade to VectorWorks 2008.