TurboTips: V-Ray Blend Material, Part 3

Calvin Bryson 3D Modeling, Artists, TurboTips, V-Ray Blend Material

The following is part of our in-depth guide to the regular V-Ray Blend Material.  It will cover the theory behind many of the features of this material, and will also provide specific examples of settings, as well as tricks to use.  While the images used are from 3ds Max, the same concepts and settings can be used for V-Ray for Maya. The information covered here will be generally useful for V-Ray for C4D, but the blend material acts quite differently in C4D.

Examples & Common Issues with V-Ray Blend Material

 

 

 

Blending Two Different Materials

This is perhaps the most common use of V-ray Blend. Imagine that you have two radically different materials that are assigned to the same object; for example, dirt spots on glass. Glass is refractive and reflective.  Dirt has very weak and blurred reflections and is not refractive at all.  So, it makes sense to create two materials and just blend them with a black and white map.

Here’s the glass material…

And here is the dirt material…

Now, we simply plug them into the Base and Coat slots, and assign a texture to the Blend Amount…

That’s it! The result looks good and you can always swap the Blend Amount texture for something different to change the dirt distribution.

Refractive layers

Most of the time, it’s fairly easy and intuitive to break down the Blend into multiple simple materials. The way they look is obvious: metal is metal, wood is wood, etc. The only exception is with Refractive layers (things like lacquer, clear coat, epoxy, etc.).  While they’re refractive in the real world, you should not make them refractive in V-ray, since it forms a strange and incorrect result.

Let’s say we have a green plastic material, to which we want to add a clear coat reflection (imagine it’s been dipped in lacquer).

The way to approach it is perhaps counter-intuitive, but works very well: set up a V-ray Material with black diffuse and 255 white reflections (fresnel off) in the Coat material slot.

For the Blend amount, use a Falloff map set to Fresnel with 1.5 IOR (acrylic). Now, lower the white color slightly, to something like 215.

And here is how the resulting shader looks. The effect is exactly what we were trying to achieve.

Bump

One of the most common problems with V-ray Blend Material is Bump. To achieve a realistic look, the same map should be featured in all the layers, especially if the mask is very high-contrast with sharp borders around patterns.

This scratched paint material has bump in white layer only.  It doesn’t look that great.

In this version, we’ve added the same bump map to the Paint material as well.

Looks better, but what if you also want to add an ‘orange peel’ effect? If you need additional bump effects, you have to change the map type in that particular layer to composite and instance the common texture in there. Now you can composite other maps on top of it, while still keeping a the common bump as well.

In future V-Ray versions (v3 and possibly 2.5), this can be made much simpler by using a V-Ray Bump Material. This functionality will allow you to add common bump to the whole material, on top of each layers existing bump.

Glossiness blend

Let’s see how we can create an advanced shader that currently is impossible with regular V-ray Material. The effect we’re looking for is a ‘tail’ for the Reflections.

First, we’ll set up a basic metal material in the base slot.

Now, let’s copy the material to the next two coat slots and gradually reduce the Glossiness value.

Finally, we just need to adjust the Blend Amount color for both coat slots. Usually, the further the reflections are blurred, the less we want the layer to be visible. Reduce the second coat amount more.

And here is the result…

To make it more interesting, you can use texture instead of color in the Blend Amount slots. Here, we’re using a simple scratch-map…

 

As you can see, there are many different ways you can use the V-Ray Blend Material… it’s not just for blending two different materials, and it can be used in much more creative ways as well.

 

This series of tutorials was made with our friends at Viscorbel.

If there are any topics you’d like to see in a future edition of  TurboTips, let us know in the comments below, or Tweet your question to @TurboSquid with hashtag #TurboTips.