Cook Torrance

Color – Specifies the color of the material.

Transparency – Specifies the transparency of the material.

Reflect Exit Color – If a ray has reached its maximum reflection depth, this color will be returned without tracing the ray further.

Hilight Glossiness Tex – Determines the shape of the highlight on the material. Normally this parameter is locked to the Reflection glossiness value in order to produce physically accurate results.

Reflection Glossiness Tex – Controls the sharpness of reflections. A value of 1.0 means perfect mirror-like reflection; lower values produce blurry or glossy reflections. Use the Reflection Subdivs parameter below to control the quality of glossy reflections. 

Anisotropy – Determines the shape of the highlight. A value of 0.0 means isotropic highlights. Negative and positive values simulate "brushed" surfaces. 

Anisotropy Rotation – Determines the orientation of the anisotropic effect in a float value between 0 and 1 (where 0 is 0 degrees and 1 is 360 degrees). 

Subdivs – Controls the quality of glossy reflections. Lower values will render faster, but the result will be noisier. Higher values take longer, but produce smoother results.

Cutoff – This is a threshold below which reflections/refractions will not be traced. V-Ray tries to estimate the contribution of reflections/refractions to the image, and if it is below this threshold, these effects are not computed. Do not set this to 0.0 as it may cause excessively long render times in some cases.

Trace Reflections – If this is disabled, reflections will not be traced, even if the reflection color is greater than black. You can turn this off to produce only highlights. Note that when it is disabled, the diffuse color will not be dimmed by the reflection color.

Trace Depth – Represents the maximum number of bounces that will be computed for reflections and refractions. The individual material reflection/refraction depth settings are still considered, so long as they don't exceed the value specified here.

Dim Distance – Specifies the distance after which the reflection rays will not be traced.  

Distance – Specifies a distance after which the reflection rays will not be traced.

Falloff – A fall off radius for the dim distance. 

Reflect Exit Color – If a ray has reached its maximum reflection depth, this color will be returned without tracing the ray further.

Affect Alpha – Allows the user to specify which channels will be affected by the reflection of the material.

Color only – The reflection will affect only the RGB channel of the final render.
Color+alpha – The material will transmit the alpha of the reflected objects instead of displaying an opaque alpha.
All channels – All channels and render elements will be affected by the reflections of the material.

Glossy As GI – Specifies on what occasions glossy rays will be treated as GI rays:

Never – Glossy rays are never treated as GI rays.
GI – (Default) Glossy rays will be treated as GI rays only when GI is being evaluated. This can speed up rendering of scenes with glossy reflections.
Always – Glossy rays are always treated as GI rays. A side effect is that the Secondary GI engine will be used for glossy rays. For example, if the primary engine is irradiance map and the secondary is light cache, the glossy rays will use light cache (which is a lot faster).

Reflect Exit color - If a ray has reached its maximum reflection depth, this color will be returned without tracing the ray further.

Back Side – When disabled, V-Ray calculates the reflections only for the front side of the objects. When enabled, V-Ray calculates the reflections for the back sides of the objects too.