Reflection (computer graphics)

Reflection in computer graphics is used to emulate reflective objects like mirrors and shiny surfaces.

Reflection is accomplished in a ray trace renderer by following a ray from the eye to the mirror and then calculating where it bounces from, and continuing the process until no surface is found, or a non-reflective surface is found. Reflection on a shiny surface like wood or tile can add to the photorealistic effects of a 3D rendering.

Polished - A polished reflection is an undisturbed reflection, like a mirror or chrome.
Blurry - A blurry reflection means that tiny random bumps on the surface of the material cause the reflection to be blurry.
Metallic - A reflection is metallic if the highlights and reflections retain the color of the reflective object.
Glossy - This term can be misused. Sometimes, it is a setting which is the opposite of blurry (e.g. when "glossiness" has a low value, the reflection is blurry). However, some people use the term "glossy reflection" as a synonym for "blurred reflection". Glossy used in this context means that the reflection is actually blurred.

Examples

Polished or mirror reflection

Mirrors are usually almost 100% reflective...

Metallic reflection

The large sphere on the left is blue with its reflection marked as metallic. The large sphere on the right is the same color but does not have the metallic property selected.

Normal (nonmetallic) objects reflect light and colors in the original color of the object being reflected. Metallic objects reflect lights and colors altered by the color of the metallic object itself.

Blurry reflection

The large sphere on the left has sharpness set to 100%. The sphere on the right has sharpness set to 50% which creates a blurry reflection.

Many materials are imperfect reflectors, where the reflections are blurred to various degrees due to surface roughness that scatters the rays of the reflections.

Glossy reflection

The sphere on the left has normal, metallic reflection. The sphere on the right has the same parameters, except that the reflection is marked as "glossy".

Fully glossy reflection, shows highlights from light sources, but does not show a clear reflection from objects.