More thumping of said horse... Dirt on noise turns into, lost detail. Dirt on vanilla turns into detail seen. Its the same crack "decal" on both textures. (Not exactly true, I had to turn the brightness down for it to even show up on the brick.)
"if you think it's dirty... make it dirtier?" Jesus... Like SF said, they need to teach how to think about dirt and where/why it collects and the type of wear and tear elements have on structures... i don't know what kind of class you're taking. It may have been mentioned before, i'm at work though... so i'm not going to…