[farshizzo]

Try adding the following line to your script:

viz.directormode(viz.DIRECTOR_FAST)

This tells Vizard to allow Python threads to run while Vizard is drawing. Technically speaking, this will instruct Vizard to relase the GIL while rendering. For more information about the GIL and how Python threads behave, have a look at this page, http://docs.python.org/api/threads.html