The Material Output node connects all nodes in the V-Ray Shader Node Tree to the scene. Any nodes not connected in any way to the Material Output are not reflected in the scene.

UI Path: ||V-Ray Node Editor|| > Shader > Add > V-Ray Material Output

Don't Override – This option disables the Material ID and Multimatte ID overrides.

Material ID – Enable this option to set a custom Material ID for the entire material, overriding any Material IDs already present in the setup.

Multimatte ID – Enable this option to set a custom Multimatte ID for the entire material, overriding any Multimatte IDs already present in the setup.

Render Stats – Enable to specify additional settings for the entire material. These settings override any settings already set for the individual components of the material.

Primary Visibility – Specifies whether the material is seen by the camera rays.
Visible In Reflections – Determines whether the material is visible in reflections.
Visible In Refractions – Determines whether the material is visible in refractions.
Casts Shadows – Determines whether the material casts shadows in the scene.
Receives Shadows –  Determines whether shadows cast by other objects in the scene are visible on the material.
Visible To GI – Determines whether the material is visible in Global Illumination.

Wrapper – Enable to override the material and use a Mtl Wrapper material instead. This option is useful for debugging and testing.

See the Mtl Wrapper page for information on its Matte Properties, Additional surface properties, and Miscellaneous options.

Round Edges – Enable to apply a round edges effect to the entire material.

Radius – Specifies a radius for the round edges effect. Since the actual geometry is not being changed and only the normals of the faces are affected large values here may produce undesirable effects.

Consider Same Object Only – When enabled, the rounded corners are produced only along edges that belong to the same object that has the attribute applied. When disabled, rounded corners are produced along edges formed when the object with the attribute intersects other objects in the scene.

Corners – Chooses which edges are considered in the calculation. Possible options are:

Convex and Concave – Considers all edges.
Convex Only – Only applies Round Edges effect to edges with convex angles. 
Concave Only – Only applies Round Edges effect to edges with concave angles.