After adding the plug-in you can either create a snow or rain object from that. Each one has methods that allow you to set the size, speed, and wind for the particles. Here is a sample script that you can use to change the effects.
Code:
import viz
viz.go()
viz.add('tut_ground.wrl')
precip = viz.add('precipitation.dle')
snow = precip.snow(1)
import vizmenu
menu = vizmenu.add()
OptionsMenu = menu.add('Options')
SpeedSlider = OptionsMenu.add(viz.PROGRESS_BAR,'Default','Speed')
SizeSlider = OptionsMenu.add(viz.PROGRESS_BAR,'Default','Size')
WindSlider = OptionsMenu.add(viz.PROGRESS_BAR,'0.00','Wind')
WindSlider.set(0.5)
def onSpeed(pos):
val = pos*10
snow.setSpeed(val)
SpeedSlider.message('%.2f'%(val))
vizact.onslider(SpeedSlider,onSpeed)
def onSize(pos):
val = pos*0.1
snow.setSize(val)
SizeSlider.message('%.2f'%(val))
vizact.onslider(SizeSlider,onSize)
def onWind(pos):
val = pos*20 - 10
snow.setWind([val,0,0])
WindSlider.message('%.2f'%(val))
vizact.onslider(WindSlider,onWind)