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         Tutorial 2: Advanced Specularity Control

         One of Gaffer's main features is its Specularity control. It
         gives the user enormous influence over the behavior of specular
         highlights, including defining the exact shape, blending, width,
         sharpness, anisotropy, edge strength and falloff, and even color
         of the highlight. Multiple highlights can also be superimposed,
         which is critical for many surfaces such as paint. LightWave
         gives you one single control over specularity shape,
         "Glossiness." Gaffer provides thirty-two separate controls. This
         much control may seem like outrageous overkill, but in fact it's
         a necessity to match the behavior of real surfaces.

         In our last tutorial we set the stage for surfacing an urn.
         We'll begin by loading "spec_urn.lws" into Layout. This is what
         your scene should look like if you completed the last tutorial.
         What we want to achieve here is to create a very polished and
         thick lacquered, painted surface. This kind of surface has a
         distinctive, rich look, even without texturing, due to its
         complex specular behavior. We'll start by coloring the urn and
         starting to move towards the basic characteristics of a red,
         lacquered paint. Open the surfaces panel and set the urn's
         surface color to 200-0-0. Set the diffuse value to 75%,
         specularity to 100% and reflectivity to 10%. For now, let's
         disable the fill lights so they're out of the way (we'll turn
         them back on later.) Go into Gaffer's options and set the
         "boost" value for the "Fills" to 0%. Gaffer has a small surface
         preview to help see the effect of different controls, so lets
         set that up so we don't have to do multiple test renders. We
         have to tell Gaffer about the kind of surface we want to
         preview, so in the bottom-left of Gaffer's interface, set the
         preview diffuse to 75%, preview specular to 100% and preview
         color to 200-0-0. This matches the basic surface settings that
         are set in Layout's surface panel. The preview now shows a
         simple shaded red ball, which will update as we set the more
         advanced Gaffer options.

         A surface such as the one we are trying to create has a very
         tight hotspot (usually the same color as the light causing the
         spot since it's actually a reflection of sorts) and a broad
         underlying hotspot caused by the coating or layers of paint.
         This is usually reflected as the color of the paint itself.
         Let's first create the bright, white, center hotspot. Set
         Gaffer's "primary specularity" to 100% and the color to
         225-225-225. Set "Gloss" and "Sharp" to 90%. These numbers were
         chosen simply by watching the preview as different values were
         chosen to match the behavior we had in mind. Now we'll add the
         second specularity, which has a broader, colored, highlight. Set
         the "Secondary Specularity" to 100% to activate a second
         specularity channel. For this type of surface we want this
         hotspot to be a bit brighter tint than the base surface's color
         to give it an electric look, so set the color to 225-0-0. The
         preview shows this effect. We want a slightly tighter highlight
         than the default (but not as tight as the first, white,
         specularity) so set "Gloss" to 70% and leave "Sharp" at 50%.
         We're ready for a a test render, so close Gaffer's panel and
         re-enter Layout. Open the camera panel and turn on "Trace
         Reflections". Render a frame.

         Looking at the frame, we're getting there but the secondary
         hotspot needs more work. It's too narrow and too bright. Go back
         into Gaffer. By experimenting (and again watching the preview)
         we set "Gloss" to 80% and "Sharp" to 25%. Bringing the sharp
         value down will broaden the hotspot while raising gloss will
         compensate for the difference by keeping the hotspot visible and
         not allowing it to be washed out. Finally, let's bring the color
         down a bit, to about 172-0-0. We can do this one of two ways.
         One is to open the color panel and manually adjust the tint. A
         second, quicker, way is to right click and drag on the color
         gadget itself to raise and lower its brightness.

         Exit Layout again and render the scene. The urn, with no
         textures at all, is starting to have some real character. Yet
         all we've done is tweaked its surface shading! This illustrates
         how important the shading model really is when you're trying to
         create photoreal effects. The next tutorial will keep using this
         urn as an example, and show the effect of anisotropic shading.

