The only way I've found is to count bricks. As far as I know they haven't worked out the scale thing between C4D and VectorWorks. Have you found that your models import into C4D at the right scale? Once you do get the materials looking good in C4D you can set up a translator file with the material exchanger plugin. I guess you still need to scale them, though. I "solve" this problem by not doing any material work in VectorWorks, eyeing it in C4d, and remembering the necessary scaling to make it look like that.
When I export models to C4D, often extruded polygons and added/subtracted solids do not translate, appearing as empty shapes. The polygons are closed, and often quite simple (rotated rectangle). And, sometimes objects that I successfully exported the last 20 times suddenly have the same problem. 1. Can I fix this? 2. Does the latest version of the plug-in fix it?