Can you post some sample code? The following script shows one way to use a quad to fade the scene in/out:
Code:
import viz
import vizact
viz.go()
viz.addChild('gallery.osgb')
fadeQuad = viz.addTexQuad(parent=viz.ORTHO)
fadeQuad.setScale([5000,5000,1])
fadeQuad.color(viz.BLACK)
fadeQuad.alpha(0)
fadeQuad.alignment(viz.ALIGN_LEFT_BOTTOM)
fadeQuad.visible(0)
fadeOut = vizact.sequence( vizact.method.visible(1), vizact.fadeTo(1.0,speed=1.0) )
fadeIn = vizact.sequence( vizact.fadeTo(0.0,speed=1.0), vizact.method.visible(0) )
vizact.onkeydown(' ', fadeQuad.runAction, vizact.choice([fadeOut,fadeIn]) )