Ian wrote:I am guessing .. it was only used for shadows in games.
There are lots of translucent polygons used throughout different games. For example: the windshields in Scud Race (and Daytona 2, probably), the entire Carnotaurus boss in Jurassic Park (he dynamically fades to invisible and back), and I suspect some (but not all) of the water on LA Machineguns' second stage (you can just barely see the frogmen beneath the surface).