is this by design? My initial thought was that it would return cpVect(0,0) instead?
I haven't actually any use case for this method and the current behavior might be the desired one. Im just working through the api for pymunk and trying to understand what the different methods does..
http://www.pymunk.org - A python library built on top of Chipmunk to let you easily get cool 2d physics in your python game/app