Glossiness - Concepts

Surfaces may be made to look shiny or glossy by adding a Glossiness value to their surface properties. Glossiness refers to the shininess and apparent smoothness of a surface. A highly gloss surface appears very smooth and shiny (e.g. polished marble), while a low gloss surface appears somewhat rough and dull (e.g. a hardwood floor with a low satin finish).

This attribute is only visible in Ray Trace images and does not affect the numeric and radiosity calculations in any way. It is simply a post process "layer" that is added to the surface when Ray Trace images are created.

Glossy surfaces will increase the number of rays and ray tracing time - generally by a factor of 3 to 5 times. It is strongly recommended to limit the use of glossy surfaces and/or soft shadows for presentation grade images only.

Technical Details

The range of Glossiness is 0.0001 (essentially diffuse) to 1.00 (perfectly specular). The default value is 0 - No glossiness applied. A value of 0.10 is recommended to provide a realistic appearing low gloss finish to surfaces for most applications.

Glossiness can be applied to any surface which also has a Specularity Value greater than 0 assigned, including glass (which produces a ‘frosted’ effect).

Glossy surfaces only work with specular materials where you can see the reflections of other objects. When you enable the glossy surfaces feature, AGi32 bounces 9 rays from each pixel intersection within a specular surface instead of one. The rays are 'jittered' (scattered) from the specular reflection direction based on the glossiness value. With a value of 1.0 (perfectly specular), the rays are not jittered and the reflected image is perfectly reflected (all rays are reflected in the same direction, no distortion). As the value approaches 0 (essentially diffuse), the amount of jittering increases, yielding a dull (or distorted) reflected image (the rays are not reflected in the same direction). As a result, you will not notice glossy surface reflections from strongly curved surfaces. Again, when Glossiness = 0, that does not mean that the surface is diffuse. Rather, it means that glossiness is not considered; no glossiness is applied.

The effect of the glossy reflections becomes more apparent as the distance between the glossy surface and the reflected object increases.

10% Specular Floor; Glossiness at Default Level (0) - Specular Reflection is consistent for all parts of reflected image.	10% Specular Floor; Glossiness at 0.1  - Effect of low gloss surface is most apparent at bottom of image, at farthest point of reflection.
Specular Interior Glass
20% Specular Interior Glass, 2 Panels assigned 10% Glossiness Factor