In our previous post, we had introduced the sheen parameter from V-Ray 5. Now we would like to give a look at another update of the vraymaterial: the Coat parameter.

This feature is pretty useful when on a material we need to add an extra thin layer of reflectivity. It’s a typical case when we’ve to deal with materials in which we need to add a coat paint for example.

The varnished wood is one of them, where on top of the original surface there’s an addition of transparent paint that makes the surface more reflective and shiny.

Before this feature, we were doing this with the vrayblend material using the Shellac mode but most of the time that option created artifacts in the final rendering.

So to set up a varnished wood we proceed like this:
we create the base wood material with its diffuse map, reflection pure white, glossiness map e bump map.

This is what you get:

Now we add the varnished coat layer.
First of all, we set a coat amount which is how much reflective the final coat will be. When it is set to zero there is no coat calculated but when we increase the value, we can start seeing the extra reflectivity.
Then we specify the coat color, which is the tint that the reflection will acquire. If the paint is neutral, we can set a whitish color. In this example the color is white 230.

Coat amount 0.2
Coat amount 0.2
Coat amount 0.2
Coat amount 0.2

It is pretty nice to see that even if increase the value to 1 for the coat amount (it is the max), we can still see the differences provided by the normal map.

Now let’s play a bit with the coat glossiness. Here we decide how much to gloss the coat amount reflectivity.

You can also think to add a map into this slot to make variations as if the paint has not been added uniformly on the surface.

Coat glossiness with a noise map

The coat IOR represents the behavior of our coat reflectivity and it’s related to the coat material we want to replicate. If it’s a non-metal, the ior value has to stay between 1.4 and 1.6. If we want the coat reflectivity to look more like a metal, then we can increase the IOR value.

Thanks for reading and I hope to see you at SoA Academy soon.


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