I believe that it's all there and that it has been there ever since rFactor was released, it has just not been enabled. Simbin games use the same engine, the only difference is they have functions like rain enabled. There is a raindrop tga in the commonmaps mas, there is everything needed in rFactor to make a dynamic wet track with rain, it's just not turned on. I mentioned in my first posts that this is probably not worth pursuing because rf2 is around the corner, but its a fun thing to do when I'm free and aren't doing anything else. It is more so a theory I had that I wanted to test, nothing more. As Emery points out, there are a lot of functions that take the realism away from it and making things like rain on the windscreen and wipers work is not possible in this case. I think there is the possibility that someone could write a dll to take advantage of the rain but coding is not my thing.