GGX

 Color Tex – Specifies the color of the material.

Transparency Tex – 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).

Soften Edge – Softens the edge of the BRDF at light/shadow transitions

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.

Use Interpolation – Turns caching on. V-Ray can use a caching scheme similar to the irradiance map to speed up rendering of blurry reflections. The options for the interpolation of blurry reflections are also very similar to the options for the irradiance map. Note that it is not recommended to use interpolation for animations, since this may cause severe flickering.

Min Rate –  Determines the resolution for the first interpolation pass. A value of 0 means the resolution will be the same as the resolution of the final rendered image, which will make the interpolation similar to the direct computation method. A value of -1 means the resolution will be half that of the final image and so on.

Max Rate – Determines the resolution of the last interpolation pass.

Samples – The number of samples that will be used to interpolate the blurry reflections at a given point. Larger values tend to blur the detail, although the result will be smoother. Smaller values produce results with more detail, but may produce blotchiness if the Subdivs parameter has been set too low.

Color Thresh – Controls how sensitive the interpolation algorithm is to changes in the color of reflections. Larger values mean less sensitivity and smaller values mean more sensitivity and better results.

Normal Thresh – Controls how sensitive the algorithm is to changes in surface normals and small surface details. Larger values mean less sensitivity; smaller values mean more sensitivity to surface curvature and small details.