Normal and spec maps...

Spur

Hi everyone! I've always been under the impression that in order to really make your normal map pop, you needed a spec map too. Even for something that is mostly flat in appearance, you would need a tiny bit of spec right? Does it really make sense to have just a diffuse and normal map plugged in a shader, with no spec? Or am I looking at it totally wrong?

Dylan Brady

sometimes its fine. but usually if you want to get those little details like dirt, scratches, any kind of small surface detail you need to use a spec to break up the hightlights.
If you don't use a spec you can put noise in your normal map, but that sometimes looks horrible, like the dirt is actually a huge blob of wax or something.

Better to leave the surface of your normal relatively flat, and put those things into the spec in
my books.

For me the best way to get this effect is to use multiple layers of dirt/surface details (I use one for warm, blood like stainy things, one for cool purples/blues, and a few more of just greytones)

And then when your creating you spec use stark contrasts of value to get one little area to pop out from the background, either by being more shiny, or less shiny.

Eric Chadwick

The tutorials here might help you.
http://wiki.polycount.com/SpecularColorMap