Mari 4.6v4 docs:

BRDF

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 effect of the shaded surface.
Inputs \| Specular Color	dropdown	The channel controlling the specular color effect of the shaded surface.
Inputs \| Glossiness	dropdown	The channel controlling the glossy areas for highlights in the specular shaded surface.
	button	Inverts the channel values of the selected channel.
Inputs \| Reflectance	dropdown	The channel controlling the reflective effect of the shaded surface.
Inputs \| Ambient Occlusion	dropdown	The channel controlling the ambient occlusion effect of the shaded surface. Using this input overrides the ambient occlusion values stored on the object (Objects > Ambient Occlusion).
Inputs \| Emissive Color	dropdown	The channel controlling the color of the emissive (glow) qualities on the shaded surface.
Inputs \| Normal	dropdown	The channel used for input as a representation of the surface normals, added to the shaded surface. You must select either a Bump or Normal shader component in the same shader. If you attempt to use both, Normal overrides the Bump shader component.
Inputs \| Bump	dropdown	The channel controlling the bump map to show as a perturbed lighting.
Inputs \| Vector	dropdown	The channel controlling the vector field and resulting vector data from paint on the shaded surface.		This data is used by the vector inspector.
Inputs \| Displacement	dropdown	The channel controlling the displacement map and dynamic tessellation to show a more advanced preview of displacement.		This component is disabled for Ptex channels.
	button	Adds a new channel for the shader component.	Add Channel Dialog
Diffuse	text field, slider	How much of the diffuse input appears on the shaded surface.		From 0 to 1; defaults to 1.
Specular	text field, slider	How much of the specular light appears on the shaded surface.		From 0 to 1; defaults to 1.
Glossiness	text field, slider	How glossy the highlights appear on the shaded surface. The closer to 1 this is set, the more mirror-like the shaded surface appears.		From 0 to 1; defaults to .200.
Ambient Occlusion	text field, slider	How much ambient occlusion occurs on the shaded surface.		From 0 to 2; defaults to 1.
Reflectance	text field, slider	How much of the reflection appears on the shaded surface. The closer to 1 this is set, the higher the reflectiveness.		From 0 to 1; defaults to .200.
Emissive	text field, slider	How much glow the emissive channel appears to have.		From 0 to 100; defaults to 1.000.
Displacement \| Displacement Bias	text field, 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	text field, 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 \| Displacement Range	text field	What the range of displacement is. This setting is multiplied by the Displacement Scale to give the displacement.
Displacement \| Max Tessellation	text field, 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.
Bump \| Bump Weight	text field, 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 1.000.
Bump\| Bump Mode	dropdown	Displays bump quickly (Fast), accurately (Accurate), or less accurately (Fastest).		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.