Quote - Spec maps are also designed mostly for game models. With an unbiased renderer, you really shouldn't use spec maps since your specular comes from the lighting on your surface, use your bump or normal map to define the sufface and how light will react with it. 

I initially shared this point of view while writing Reality 1.0. Fortunately I decided to look a little more into this issue, and I then added support for specular maps in Reality 1.0, improved in Reality 2.0 and vastly expanded in Reality 3.

This is because specular maps actually help us specify physical properties of real materials. They are not just for games. Skin has several levels of glossiness, depending on the location of the body. For example elbows are less shiny than the face. Even on the face there are different spots that are shinier than others. There is no way Lux, or any other renderer, can calculate accurate effects of shine without a specular map. In fact I generaly reject texture packages that don't come with a specular map. It's a sign of lack of attention to details, IMHO.

Please note that a specular map is a completely different thing than a reflection map. Reflection maps have no business in physically-based rendering and they are often employed by game engines. Many Poser texture packages come with reflection maps and Reality ignores those map.

On the other has a specular map is a very helpful tool to improve the realism of materials.

In Reality 3 there is also an option to use a map to drive the glossiness strength through a map .

Hope this helps.

Paolo

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