My problem is, how do I make it appear there are drops and rain streaks on the outside of the glass. My first idea was to make an opacity map with the drops and streaks on it, but I need the elements to have specularity, and I'm not sure am opacity mao could do that. I could, displace the opacity plane, but that doesn't strike me as a good idea as my scene already contains 1546 objects with 3,660,816 faces, so adding several poly heavy planes would likely over stress my crappy computer which is already breathing heavily and moaning about the scene.
So, any ideas or tips anyone could share with me about how to do this? I know glass is a common problem in texturing, but surely someone done wet glass before. I'd appreciate a little help if anyone has any ideas. I'm trying to take this scene to a level of detail I've never done before, and this is about my last addition to it before the final render.