This is a response found on the Vectorworks Forum site to a user with the same issue
Export from VW as .3ds (check the export textures as either jpg or png). Import 3ds into SU.
Import it into a blank/clean SU document. There is an option when importing to merge coplanar faces which you may want to do.
The scale can be ‘interesting’ which is why it is best to put it into a blank doc and rescale the object. The hierarchy can also be a bit odd so some tidy up work with the component in SU will be needed.
Overall its not bad depending upon the complexity of the object(s) from VW
(Include a 1m (or 1 ft) cube in the export so you can rescale based on that then delete in SU when done)
Hopefully this will work for you.