The following is an 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.
The V-Ray Blend Material could be best described as a utility material. It does not have any shading options, so it combines multiple other shaders in different ways.
The layout is simple: you have a Base material and nine Coat materials. In fact, they all function in the same way (similarly to layers in Photoshop), so you have a ten-layer stack. Each layer after Base has a Blend amount, Color, and Map.
Blends can be as complex as you want them to be. Since you’re not limited to the ten slots, you can always add another blend in the last layer slot and keep piling on layers. However, in the real world, this isn’t the most practical way to do things. Each new layer makes the render slower, since V-ray has to calculate all the materials in the blend, and then blend them together. This means you could easily bog down your render times if you get too carried away.
Most of the time, 4-5 layers should be the absolute maximum to use, with 2-3 being the norm. It’s also easier to manage the shader with fewer layers.
Let’s see how they work.
We’ve set up a Red material in the Base slot and a Blue material in the first Coat slot. You can see how the Blend amount color affects how much of the second layer is visible. It’s a simple opacity scale: black makes the coat invisible, and white makes only the coat visible. Everything in between is a mix of the two.
Of course, you can also use a map in the Blend amount slot. The map needs to be grayscale and the Gamma, when loading the image, should be set at 1.0 for correct results.
Here’s an example with a black and white map in the slot.
You can also mix the Map with the Blend amount color, using this numerical value. At 100, it only uses the map; at 70, it uses 70% of the map; and at 30, 30% of the color, etc. This is great when you need to fine-tune the exact amount of blending, without changing the texture itself.
So, what about adding another coat layer?
Once you add another material to the list, everything above it is combined and treated as a single base layer (exactly as in Photoshop, except the layer list is reversed- from the top, down).
If we add a Green layer to our Red and Blue, the result is not Red+Blue+Green, it is Purple+Green, since the first two layers get mixed at 50%, and the result is mixed at 50% with the next layer.
Lastly, the Additive mode check box always needs to be turned OFF for physically correct renderings. It is only there to mimic the functionality of a regular 3ds max Blend Material, but should not be used if you want believable shaders.
Join us next week: now that we have the basics out of the way, we can look at some fun ways to use the V-ray Blend Material.
This series of tutorials was made with our friends at Viscorbel.
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