Type - this determines whether the map acts as a reflection map or a refraction map. Note that the VRayMap does not automatically detect this type; you need to set this manually.
Reflect - when this option is chosen VRayMap will act like a reflection map. Then the Reflection params section can be used for controlling the settings of the map (Changing settings inRefraction params section will have no effect on the map).
Refract - when this option is chosen VRayMap will act like a refraction map. Then the Reraction params section can be used for controlling the settings of the map (Changing settings inRefraction params section will have no effect on the map).
Reflection params
Filter color - multiplier for the reflections. Do not use the spinner in the material to set the strength of reflections. Use this filter color instead (photon map will not be correct otherwise).
Reflect on back side - this checkbox forces V-Ray to trace reflections always. Using this option in conjunction with a refraction map increases rendering times.
Glossy - turns glossy (blurry) reflections on.
Glossiness - the glossiness of the material. A value of zero means extremely blurry reflections. Higher values makes reflections sharper.
Subdivs - controls the number of rays sent out to evaluate the glossy reflection. More rays mean smoother reflection, but more rendering time.
Max depth - maximum ray depth for the map. The map will return the Exit color for rays of greater depth.
Cutoff thresh - reflections which contribute little to the final value of an image sample will not be traced. The cut-off threshold sets the minimum contribution for a reflection to be traced.
Exit color - the color to be returned when the maximum ray depth has been reached but the reflection has not been computed completely.
Refraction params
Filter color - multiplier for the refraction. (see Filter color in Reflection params section).
Glossy - turns glossy (blurry) refractions on.
Glossiness - (see Glossiness in Reflection params section).
Subdivs - (see Subdivs in Reflection params section).
Fog color - V-Ray allows you to fill refractive objects with fog. This is the color of the fog.
Fog multiplier -multiplier for the Fog color. Smaller values produce more transparent fog.
Max depth - the maximum ray depth for the refractions. (see Max depth in Reflection params section)
Cutoff thresh - (see Cutoff thresh in Reflection params section)
Exit color - (see Exit color in Reflection params section)
