Surfacing - Blender Foundations: The Essential Guide to Learning Blender 2.6 - page 167

Now, we only bring it back up for things that really require it. What kind of stuff requires a specular
highlight? Things with gloss and shine: lacquered wood, glass, polished metal, many plastics, wet pavement.
Remember when we mentioned that a material shouldn't reflect more light than it receives? Well, that
comes into play right now. Our walls are a bit glossy as we noted when we selected the Lambert base
shader. So, it would make sense that they exhibit some specular highlighting as well. The Diffuse Intensity
is set at 0.9, meaning that the surface is already reflecting 90% of the light it receives. Using our previous
rule, the Specular Intensity shouldn't be higher than 0.1 (0.9 + 0.1 = 1.00). It might even be lower.
At this point you might be looking at a material preview with these settings and thinking that it doesn't
show much at all. You would be correct. Crank the values up until it's obvious and you lose your (1)
subtlety and (2) believability.
In addition to Intensity , there are three other options with specularity. The first is Color . Unless you're
dealing with a colored metallic substance, leave it pure white. Specular highlights should show the color
of the light source without alteration. When dealing with a metallic surface though, the specular should
be adjusted to match the diffuse color. That's just the way that colored metals do it.
The next option is the Specular Shader . Just like with Diffuse, there are a number of choices, some
more useful than others. The one that fits the most real-life cases is the Blinn shader, which we've chosen
for our walls. Chose Blinn as your default. However, if you're working with a high-gloss material, choose
either Phong or CookTorr (it's nearly impossible to tell the difference between the two, so flip a coin).
Finally, each of these specular shading models has a way of controlling the size of the highlighted area.
The Hardness value runs from “extremely diffuse highlight” at 0 through “tight and highly focused” at
511. Higher values mean smaller, more intense highlights. For most surfaces, start testing this value around
25. Materials with a high gloss should have this set over 128 to produce the proper highlighting. For
everything else, though, you'll either have specularity turned off completely or set to very low intensity
levels. Be careful dropping this value below 10, as it is so diffuse that the highlighted area actually becomes
most of the portion of the object facing the lamp. In the example scene, the hardness of the walls is set
to 11—a very diffused highlight that is close to covering too much area.
Let's move one more panel downward before we move on to texturing. (Move on, you say!? But what
about all of those other buttons? We'll either deal with them later in more advanced examples, or their
use is so specialized that they don't have a place in a beginner's topic.) The Shading panel controls options
that apply to the way Blender handles shading (brilliant!), regardless of the individual shader choices you've
made in the other panels. For now, the only one we are concerned about is Cubic Interpolation . Really,
this should be enabled as a default for every material you create. It provides a more natural transition from
the lit portion of an object to the unlit portion.
Varying Material Properties with Textures
So far, it seems that the main properties of a material are the diffuse color and intensity and the specular
color and intensity. But nothing in the real world has a perfectly uniform color. To vary these properties
(and others you haven't used yet) across the surface, we use Textures . Textures can be of two types: image