Mari 4.5v2 docs:

VRayMtl

Note: Results may not be as expected if you do not use the Environment Light in the Lights palette when using this shader.

Control	Type	What it does	Dialog	Notes
	toggle	Toggles the influence of channels connected to the shader without disconnecting them from the shader input.		Displacement is toggled off by default.
Inputs \| Diffuse Color	dropdown	The channel controlling the diffuse color of the material.		The actual diffuse color of the surface might also be affected by the reflection and refraction colors.
Inputs \| Opacity Map	dropdown	The channel containing the opacity map (to determine which parts of the material are opaque or translucent) for the material.
Inputs \| Diffuse Roughness	dropdown	The channel specifying areas of roughness on the shaded surface, so that the diffuse of rougher materials appears flatter.
Inputs \| Self-Illumination	dropdown	The channel specifying the areas on the material that are self-illuminated.
Inputs \| Reflection Color	dropdown	The channel controlling the color on the areas of the material where light is reflected.
Inputs \| Highlight Glossiness	dropdown	The channel specifying the areas on the material where there is glossiness on a highlight.
Inputs \| Reflection Glossiness	dropdown	The channel specifying the areas on the material where there is glossiness on a reflective surface.
Inputs \| Anisotropy	dropdown	The channel specifying the areas on the material that have an anisotropic effect.
Inputs \| Anisotropy UV Coords	dropdown	The channel specifying the coordinates for where anisotropic light is reflected.
Inputs \| Rotation	dropdown	The channel specifying the direction of the anisotropic rotation.
Inputs \| Refraction Color	dropdown	The channel controlling the color of the areas on the material where light is refracted.
Inputs \| Refraction Glossiness	dropdown	The channel specifying the areas on the material where there is glossiness on a refractive surface.
Inputs \| Fog Color	dropdown	The channel controlling the color of the areas on the material where fog (the attenuation of light as it passes through a material) appears, so that thick objects look less transparent than thinner objects.
Inputs \| Translucency Color	dropdown	The channel controlling the color of the areas of translucency (or sub-surface scattering) in a material.
Inputs \| Bump Map	dropdown	The channel containing the bump map.
	button	Inverts the channel values of the selected Bump Map channel.
Inputs \| Normal Map	dropdown	The channel containing the normal map, used as a representation of the surface normals added to the shaded surface.
Inputs \| Displacement Map	dropdown	The channel containing the displacement map for adjusting the surface of the geometry.
	button	Adds a new channel for the shader component.	Add Channel Dialog
Type	information	The shader type that you are using.
Basic Parameters \| Diffuse Color	swatch	The base diffuse color on the object for the Diffuse Color channel.
Basic Parameters \| Diffuse Amount	entry box, slider	The amount of the diffuse color that is displayed in the shader.		From 0.000 to 1.000; the default value is 1.000.
Basic Parameters \| Opacity Map	swatch	The base opacity color for the channel containing the opacity map.
Basic Parameters \| Roughness Amount	entry box, slider	How “rough” the surface is when the Diffuse Color channel is applied in the shader.		From 0.000 to 1.000; the default value is 0.000.
Basic Parameters \| Self-Illumination	swatch	The color of the light given off from the Self-Illumination channel.
Reflection \| BRDF	dropdown	What type of highlights and glossy reflections are used for the material: Phong, Blinn, Ward.
Reflection \| Reflection Color	swatch	The color reflected from the material in areas specified in the Reflection Color channel.
Reflection \| Amount	entry box, slider	The amount of the Reflection Color that is displayed in the shader.		From 0.000 to 1.000; the default value is 1.000.
Reflection \| Lock highlight and reflection glossiness	checkbox	Locks the values for the Highlight Glossiness and Reflection Glossiness fields so that they match.		Locked by default.
Reflection \| Highlight Glossiness	entry box, slider	Controls the shape of the highlight on the material and is locked to the Reflection Glossiness value, unless the Lock highlight and reflection glossiness field is disabled.		From 0.000 to 1.000; the default value is 1.000.
Reflection \| Reflection Glossiness	entry box, slider	Determines the sharpness of the reflections, with 1.0 being perfectly mirror-like, and is locked to the Highlight Glossiness value, unless the Lock highlight and reflection glossiness field is disabled.		From 0.000 to 1.000; the default value is 1.000.
Reflection \| Use Fresnel	checkbox	If enabled, the reflection strength is dependent on the viewing angle of the surface, and the index of refraction.		Enabled by default.
Reflection \| Lock Fresnel IOR to Refraction IOR	checkbox	Lock the values for the Fresnel index of refraction to the values of the Refraction IOR field.		Locked by default.
Reflection \| Fresnel IOR	entry box, slider	The index of refraction used for calculating the Fresnel reflections.		From 0.000 to 10.000; the default value is 1.600.
Anisotropy \| Anisotropy	entry box, slider	Determines the amount of the anisotropic effect, with a value of 0.0 being isotropic (uniform in all orientations), while negative or positive values simulate the effect of a brushed surface.		From -1.000 to 1.000; the default value is 0.000.
Anisotropy \| Anisotropy Rotation	entry box, slider	The orientation in degrees of the anisotropic effect.		From 0.000 to 1.000; the default value is 0.000.
Refraction \| Refraction Color	swatch	The color displayed when the light is refracted in areas specified in the Refraction Color channel.
Refraction \| Amount	entry box, slider	The amount of the Refraction Color that is displayed in the shader.		From 0.000 to 1.000; the default value is 1.000.
Reflection \| Refraction Glossiness	entry box, slider	Determines the sharpness of the refraction, with 1.0 being perfectly glass-like refraction.		From 0.000 to 1.000; the default value is 1.000.
Refraction \| Refraction IOR	entry box, slider	The index of refraction for the material, determining how light bends when crossing the material's surface. If the value is set to 1.0, then the light doesn't change direction.		From 0.000 to 10.000; the default value is 1.600.
Refraction \| Fog Color	swatch	The color of the material in areas specified in the Fog Color channel.
Refraction \| Fog multiplier	entry box, slider	The strength of the fog effect, with lower values giving the material a more transparent look and higher values a more opaque look.		From 0.000 to 10.000; the default value is 1.000.
Refraction \| Fog bias	entry box, slider	The way the fog color is applied to the material. Adjusting the slider allows you to change how thin or thick areas of the object appear.		From -3.000 to 3.000; the default value is 0.000.
Subsurface scattering \| On	checkbox	Enable or disable subsurface scattering for the material.		Disabled by default.
Subsurface scattering \| Translucency Color	swatch	The color under the material in areas specified in the Translucency Color channel.
Subsurface scattering \| Fwd/back coeff	entry box, slider	Controls the direction of scattering for a ray, with 0.0 only scattering away from the surface, 0.5 potentially scattering forward or backward in relation to the surface, and 1.0 only ever scattering back towards the surface.		From 0.000 to 1.000; the default value is 1.000.
Subsurface scattering \| Scattering coefficient	entry box, slider	The amount of scattering that happens within the object, with 0.0 scattering in all directions and 1.0 continuing in the same direction inside the sub-surface volume.
Bump \| Bump Weight	entry box, slider	How much weight the bump map has. Lower values are smaller bumps, higher values are larger and more obvious displacements.		From 0 to 10; defaults to 0.100.
Bump \| Bump Mode	dropdown	While Fastest is very fast, it works better with live procedural layers rather than painted or cached layers.		While Fastest is very fast, it works better with live procedural layers rather than painted or cached layers.
*Bump* \|Bump Space	dropdown	UV - Normals are calculated relative to the UV coordinates space. The UV Bump Space mode is the more traditional approach but can lead to noticeable seams and color variations. World - Normals are calculated relative to the World coordinates space. Using the World Bump Space mode gives a more seamless result.		By default, Bump Space is set to UV.
Displacement\| Displacement Bias	entry box, slider	How much the white or black values are pushed or pulled from the surface.		From 0 to 1; defaults to 0.500.
Displacement\| Displacement Scale	entry box, slider	What the range of displacement is. This setting is multiplied by the Displacement Scale to give the displacement.
Displacement\| Displacement Range	entry box, slider	How much displacement is applied to the shaded surface. Lower values equal smaller displacement; higher values equal larger and more obvious displacement.		From 0 to 1; defaults to 0.500.
Displacement\| Max Tessellation	entry box, slider	How many texels the surface is tessellated to.		From 1 to 64; defaults to 10.
Displacement\| Perturb Normals	dropdown	Selecting yes changes the displacement so that displacement moves the surface but leaves the surface normals as they are.
'Display Tweaks'\| sRGB to Linear Color Swatches	checkbox	Convert the values of the colors from the color swatches from sRGB to Linear.		Enabled by default.
'Display Tweaks'\| sRGB to Linear Color Channels	checkbox	Convert the values of the colors from the color channels from sRGB to Linear.		Disabled by default.
'Display Tweaks'\| Turn ON Environment Light Bounce	checkbox	Set whether the object receives one extra light bounce hit from the environment light.		Disabled by default.
'Display Tweaks' \| Light Falloff	dropdown	Set whether the light fall off for Mari's point lights is Linear, Inverse,or Inverse Square.
'Display Tweaks'\| Decay Rate	entry box, slider	The rate of the light fall off.		From 0.010 to 1; defaults to 1.
'Display Tweaks' \| Ambient Occlusion Amount	entry box, slider	The amount of ambient occlusion.		From 0 to 1; defaults to 1.
'Display Tweaks' \| Render Elements	dropdown	Determines how elements of the shader are rendered, according to: • Beauty • Diffuse • Specular Highlights • Reflection • Refraction • Sub-Surface Scattering • Self-Illumination • Thickness Map Preview
'Display Tweaks'\| Thick Glass effect emulation	checkbox	Set whether or not Mari emulates the look of solid/thick glass.		Disabled by default.
'Display Tweaks'\| Import Baked Thickness Map	file browser	Import a map that represents the different levels of thickness in the material.
'Display Tweaks'\| Filter Thickness Map	dropdown	Set whether a thickness filter map, for blurring any possible noise, is set to Nearest or Bilinear.
'Display Tweaks'\| Thickness Map UV Coordinates	dropdown	Determine whether the thickness map uses the Default UVs, or flips the U, V, or both U and V values.