V-Ray Material Options

Material ID

Material Id Enabled – Enables the use of Material ID.

Material ID – The color used by the Material ID render element. You can also use a shader here.

Multimatte ID – The integer ID of the material to be used by the Multimatte render element.

Round Edges

Round Edges Enabled –  Enables the round edges effect which uses bump mapping to smooth out the edges of the geometry during render time.

Radius – Specify a radius (in world units) 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 which 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 – Choose which edges are considered in the calculation. Possible options are:

Covex 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. 

Cutoff – A threshold below which reflections/refractions are 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.

Double-sided – When enabled, V-Ray calculates the shading for the back faces separately from the front faces of the material surface. When disabled, the back faces are shaded the same as the front faces.

Fix Dark Edges –  When enabled, fixes the dark edges that sometimes appear on objects with glossy materials.

LPE Label – Allows a label to be assigned, which can be used to reference the material in a Light Path Expression. This is especially useful when working with the Light Select render element to evaluate custom light contribution in the scene.