Regarding getting yaw, pitch, roll separately frm 'vizconnect.getEuler('trac') functn

[Jeff]

In this case you don't need to get the yaw, pitch, and roll values. Just get a handle to the tracker link and use the link.setEuler operator:

trackerLink = vizconnect.getTracker('headtracker').getLink()
#Keep the incoming yaw and pitch, but zero the roll
trackerLink.setEuler([None,None,0])