New Materials system....question?

[Cube Republic]

Please could anyone explain in layman terms what the 'specular exponent' in the alpha channel of the normal map is and what it does? 

 

Link for question

[Helium Loon]

Well, I haven't looked at the actual code involved, but the 'specular exponent' is a term in several shading algorithms, and it refers to an element that controls the 'tightness' of specular highlighting.  A low exponent spreads the specular highlights out, making the object appear less 'glossy', while higher exponents cause the highlight to become very tight and narrow, resulting in a very shiny or metallic specular highlight.

 

Someone more familiar with how SL is implementing this can probably give a more specific answer, though....

 

(eta:  I looked at the linked page, and yes, this is what this parameter does.  It causes the specular highlight to spread out at low values, and tighten and narrow at higher values.)

 

[Cube Republic]

Oh so like this

[Curious Hazelnut]

In very general terms, the specular map defines how reflective the texture is on a pixel by pixel basis. This would let you do something like a shiney tile with dull grout in a single texture.

The "normal map" defines which direction each pixel is facing. It's a little harder to grasp but basically it lets you put what appears to be depth into a texture on a flat surface. So the grout between the tiles appears to be sunk in a bit and perhaps the tiles look a bit curved down at the edges.