Alpha channel

[Neurological]

Greetings,

At the moment i am on a window, dirty one, wich shall be half transparent on the not dirty parts. So far i know the alpha channel only supports black and white, so transparent or not, but my alphamap is grey ofcourse, is there another way to archive this effect that a object is half transparent on certain areas?

I think there isn't another way other than use the alpha channel. Make the dirty parts more toward to white. Or another trick is to make an overlay model with just the dirty parts and menage the alpha of them separatly.