Rendering multiple glass layers

Before I start, I have to admit that I am a completely new toPhotoWorks and just trying to do a few renders with the help of abook. I would like to render a view looking through 3 or 4 parallelpanes of glass in an assembly. I have the photoworks clear glassmaterial assigned to parts, and it works fine through 2 layers, butif I add a 3rd pane, the assembly is opaque wherever all 3 overlap.I actually have only 1 part file for the glass, inserted multipletimes in the assembly, so I know there is nothing wrong with thematerial assignment, or it wouldn't even work with 2 panes. AnyIdeas? Thanks.SolidworksPhotoworks