no what i saying is hte worn parts of a very high specular value so make those parts very bright in the spec map, than because you got a high specular value there, you need to tone down the values in the diffuse map in that area, or else it will look milky.
also to really sell worn shiny metal, you pretty much NEED reflections or a cubemap.
Also, in addition to what passerby said, make sure your not using strictly noisy brushes. I see a lot of people trying to paint grunge and wear on metal with only noisy brushes and that's usually what leads to a cloudy look. Don't be afraid to layer on those worn off areas with a simple round brush with low opacity.
Millenia told me how he did his metal wear one time. He uses photo sources, using the clone stamp tool in (screen?) mode with a greyscaled+contrasted photo, onto the mask of a metal base texture. I'm not sure if this is how he does this particular effect but it's worth trying.
Consider it this way:
Every surface have reflection, not matter how you think it is matte it still reflects light ((that's why we see colors, and why during day your room is bright).
What you should do is use dark metal texture, with pure white specular and gloss (roughness) maps, to see how it works. From this point depending on engine you are using you can refer to for example: http://seblagarde.wordpress.com/2011/08/17/feeding-a-physical-based-lighting-mode/#more-107
Or just experiment on your own.
Just remember that matte surface doesn't have crisp reflections but it still reflect light. So try to avoid pure black gloss maps.
You don't need photos for metal if you are using PBR engine (like CryEngine 3), try to feed with clean textures and then on top of add wear and more color variation.
Replies
also to really sell worn shiny metal, you pretty much NEED reflections or a cubemap.
Every surface have reflection, not matter how you think it is matte it still reflects light ((that's why we see colors, and why during day your room is bright).
What you should do is use dark metal texture, with pure white specular and gloss (roughness) maps, to see how it works. From this point depending on engine you are using you can refer to for example:
http://seblagarde.wordpress.com/2011/08/17/feeding-a-physical-based-lighting-mode/#more-107
Or just experiment on your own.
Just remember that matte surface doesn't have crisp reflections but it still reflect light. So try to avoid pure black gloss maps.
You don't need photos for metal if you are using PBR engine (like CryEngine 3), try to feed with clean textures and then on top of add wear and more color variation.