V-Ray 3.0: New Features: New and Improved Shaders
V-Ray 3.0 introduces some exciting new possibilities with its new and improved shaders. Paul Hatton checks out the integration of VRMats, BRDF implementations, and other new capabilities!
V-Ray's shaders get better with every single release and V-Ray 3.0 is no exception to this rule. One of the biggest changes that will affect a lot of visualizers is the integration of VRMat materials, previously known as Vismats. These have been around for a while now but, thankfully, the time has come for their implementation to be extended to V-Ray 3.0 and 3ds Max.
For those of you who have no idea what I'm talking about, they are basically material descriptions stored in XML files. This enables V-Ray shaders to be shared across multiple applications. Very powerful! We'll also look at some of the other features that have been introduced like Microfacet GTR/GGX BRDF.
The advertised improvements
If we take a look at the headlines other than VRMats and BRDF implementations, Chaos Group has also improved opacity mapping, adding both Clip opacity and Stochastic opacity material options. These are ideal for trees and vegetation. There is also the V-RaySkinMtl, which is a dedicated skin shader with layered SSS and reflections. They've also embraced the Open Shading Language (OSL) allowing users to create custom shaders using this platform.
In smaller news they've improved the translucency of 2-sided materials and optimized volume rendering with light cache support. Great work, Chaos Group!
An introduction to VRMats
Goodbye Vismats and welcome to the main stage, VRMats! In reality, both file types will still work, but I believe that VRMats will become the norm. Chaos Group has given us a new interface that lets us create this type of material. This will take a little getting used to but you'll hopefully recognize a lot of the parameters. The new dialogue box lets you open saved VRMats as well as create your own and save those out for distribution.
Setting up a VRMat
You create a VRMat material in much the same way you create a V-Ray material. Head over to your material editor (we're using slate) and select the VRayVRmatMtl type. The properties of this material will give you a couple of button options. Click on Open Editor and, behold, it's your all-new interface! It looks pretty plain on first impression. To actually create a material type you right-click on New Material and then make your choice. If you want to create an exact replica of a V-Ray material then just choose that option.
Editing a VRMat
With your material created you'll notice multiple rollouts. The layout is different to the normal interface but the same properties are there. Edit them in the same way. If you decide to create a standard material instead as your base then you'll probably want to add layers of properties on top of it. Do this by right-clicking on Default Material, or whatever you've named it. Go to Create Layer and then go ahead and insert your new layer. This will add a new rollout to your material. This gives you the flexibility to extend even the simplest materials.
Where to find VRMats
If you're bored of editing V-Ray materials or you want to find a material that someone else has created then you've got a few options, all of which can be found through Google. The website that I tend to use the most is vismats.com because it's fairly straightforward and it has loads of free materials available. You also don't have sign up to download a material which is a massive plus for me. Simply navigate to your desired material, download, and move on to the next step.
This bit is really simple. Create a new VRMat in the same way that we did above. You'll notice there is a File… button. Click that and navigate to your VRMat or Vismat file. Double-click on it and notice it being populated into your list. The VRMat will also display a preview now. To edit this particular material simply follow through step 3 again and go to Open Editor. To tweak the material simply add layers or amend the properties that are already setup.
Introducing Microfacet GTR/GGX BRDF
One thing that I love about Chaos Group is that they listen to their users and implement requested features. One of the features that Grant Warwick had requested for a while was to have the GGX BRDF implementation. For a while now, we've had Phong, Blinn, and Ward, but to get realistic specular highlights Grant was having to blend multiple materials together with different glossiness values. Chaos Group heard the cry, implemented GGX, and now no more stacking of blend materials for this purpose. The results are brilliant!
The old way
As mentioned, Grant Warwick taught a lot of people to layer materials up to create a more accurate specular reflection. He wanted more control over how the specular highlight changed as the distance grew greater from the center. And his creative solution was to create 2 or 3 identical V-Ray materials with only the reflection glossiness value changing. He would then use a blend material to control how the specular reflection would be displayed. It's a genius implementation but also rather redundant now...
The GGX way
Now all you have to do is head over to the BRDF panel in your V-Ray material and select Microfacet GTR (GGX) from the dropdown. None of the other parameters change between types except for the GGX option you are given a GTR tail falloff parameter. This allows for finer control of the highlight shape. To further control your reflections you can soften them, where higher values are softer, e.g. 1. You can also set the anisotropy still to create brushed materials. Lower values give a vertical brushing and higher values give a horizontal brushing - great for things like metal saucepans!
While this has been a brief introduction, hopefully it has whet your appetite for exploring all the new material features in V-Ray 3.0.The V-Ray help for version 3 is incredibly helpful as well. There is a whole page or descriptions and examples on the VRayMtl so if you're ever not sure of anything, make that your first go to place. Let me just encourage you to explore those settings that you never touch - they are not usually all that scary and could help to further improve the realism of your shaders!
Pro tip: Stochastic Opacity
This is a new opacity mode introduced for things like trees and other forms of vegetation. It randomly shades surfaces as either fully opaque or fully transparent so that, on average, it appears correct. Give it a go with your next tree!
This is as simple as opening up the VRMat editor and clicking Save As. This will give you the standard dialogue box and let you save either a .vrmat or .vismat file. This can then be imported into another scene or distributed to other people.
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