Creating a gold shader in V-Ray for Maya with a metalness workflow

We are at that point again when blog posts I’ve written in the past are obsolete again. For a long time, I was happy with my metal shading workflow and didn’t see the need to update. And I was slow to embrace PBR and didn’t see the need to implement it. But after some encouragement from my colleague, I did some long-overdue research and quickly realized that it was time to re-invent my workflows again. So to test this new workflow using Metalness, I created a gold shader and compared the method to my old approach. 

My old method consisted of using the Complex fresnel OSL shader and feeding values from https://refractiveindex.info. So basically you needed to type in values for the n and k coefficients for the different wavelengths of light. It was a little bit tedious, but I only had to do it once and could then save them as presets, so it was okay.  

If you, for some reason, want to read more about the old method you can do that here: http://www.magnus-olsson.se/creating-mastering-v-ray-shaders-in-maya-lesson-02-materials-101/.

But now on the new method. With this, you don’t need any external files at all. All you have to do is punch in values provided in a chart from this article in a standard V-Ray Material: https://www.chaosgroup.com/blog/understanding-metalness#. (Worthwhile reading the rest of it as well). 

As soon as I came to terms with the fact that it was okay to have color in the diffuse slot for metal materials, I quickly grew fond of the approach. It’s quicker and simpler to set up and also takes about half the time to render compared to a gold shader with the OSL method. 

A note is that this workflow is only possible in V-Ray Next since you need the Metalness checkbox in the material. If you haven’t already upgraded, I highly recommend it. 

Creating Mastering V-Ray shaders in Maya: Lesson 02 – Materials 101

A while ago I wrote a blog post called ”Creating Mastering Vray style shaders in Maya”. My goal was to translate some of the techniques Grant Warwick uses in the course Mastering V-Ray in 3ds Max to Maya. A lot of people still contacts me about these techniques and I’ve been feeling more and more bad about how outdated they are. So I thought it was time to update this and show how I would create these shaders today. And with new features like GGX and OSL it’s both faster and simpler to do now!

This post will cover how to create a plastic and a gold shader. Basically what I do is recreate the shaders from Mastering V-Ray: Lesson 02 – Materials 101, but with an updated approach. If this is something that people will find interesting I might continue and cover other Mastering V-Ray lessons in Maya. So please comment or contact me and let me know what you think!

Let’s start with the plastic shader. This is how the node tree looked like with the old setup:

Plastic_Old_NodeTree

It requiered three different V-Ray materials (with different values for Reflection Glossiness) to be blended together. I’ve also used the RemapValue node as an equivalent to the Falloff node in 3ds Max which is not ideal since it is pretty clumsy. V-Ray 3.3 introduces a Falloff node in Maya with a lot of the same features as in 3ds Max.  I’ve only tried it briefly but I was a little bit disappointed by the lack of bezier handles. For this plastic shader I didn’t need any falloff node since I could get the desired result with a simple V-Ray material with GGX as BRDF. Here is the settings I used:

Plastic_GGX_settings

Here is a comparision between the old shader (to the left) and the new (right):

Plastic_comparison

And now on to the gold shader. I’ve used the same approach as with the plastic shader to not blend multiple materials but to rely on a single material with GGX as BRDF.  The other big difference is that I use an OSL texture for the reflection instead of using Remap Value nodes. The OSL texture is called Complex Fresnel and you can read more about it here: http://docs.chaosgroup.com/display/OSLShaders/Complex+Fresnel+shader. The way I use this is that I start by browsing to the right material on http://refractiveindex.info/ and simply type in the right values for n and k based on the wavelength (0.650, 0.510, 0.475 for R, G and B). This is how the page looks like:

Refractive_Index_Gold_red02

There is actually a shelf called ”selected data for 3D artists” and that’s a good place to start. However, I found the values for the gold there made it look to reddish, almost like copper. So I tried a few different other Pages and chose the values from the Babar and Weaver 2015 instead.

And this is how the OSL texture looks in Maya:

All of this is better explained here: http://viscorbel.com/vray-materials-part-3-metals/ so I encourage you to read that as well.

This is how the node tree looks like for the gold shader:

Gold_OSL_Node_Tree

The color correction is for purely artistic reasons to tweak the shader to your own liking. In this setup I tried to make the gold look more like the old shader. This Color Correction node is not a default node but can be created from Create – V-Ray – Create from V-Ray plugin – Texture. By multiplying the reflection with a V-Ray Dirt I make the shader slightly less reflective in occluded areas.

This is the final settings for the shader:

Gold_OSL_settings

And here is a comparision between the old shader (to the left) and the new (right):

As you can see they are not exactly identical but I think they new one is looking better so I didn’t tweak it further to match the old one. Also worth mentioning is the significant dropoff in render time between the old shader and the new.

I have some plans to continue with these blog posts and the next one up would be a Green Metallic Paint shader, which is similar to the one Grant creates in Mastering V-Ray: Lesson 04 – Advanced Material Creation Part 1. But like I said earlier, it depends if someone actually finds this interesting. So please comment and let me know what you think and what you would like to see in the future.