Zbrush displacement in V-Ray for Maya /  by Xuan Prada

It is always a bit tricky to set up Zbrush displacements in the different render engines.
If you recently moved from Mental Ray or another engine to V-Ray for Maya, maybe you should know a few things about displacement maps extracted from Zbrush.

I wrote down here a simple example of my workflow dealing with that kind of maps and V-Ray.

  • First of all drag and drop your 16 bits displacement to the displacement channel inside the shading group attributes.
  • Maya will create a displacement node for you in the hypershade. Don’t worry to much about this node, you don’t need to change anything there.
  • Select your geometry and add a V-Ray extra attribute to control the subdivisions and displacement properties.
  • If you exported your displacement subdividing the UV’s, you should check that property in the V-Ray attributes.
  • Edge lenght and Max subdivs are the most important parameter. Play with them until reach nice results.
  • Displacement amount is the strength of your displacement and displacement shift sould be half negative than your displacement amount if you are using 16 bits textures.
  • If you are using 32 bits .exr textures, the displacement shift should be 0 (zero).
  • Select your 32 bits .exr file and add a V-Ray attribute called allow negative colors.
  • Render and check that your displacement is looking good.
  • I’ve been using these displacement maps. 16 bits and 32 bits.

Vray sss test /  by Xuan Prada

Just testing Vray’s SSS shader for realistic skin look-dev purposes.
I ended with the theory that would be quite simple to set-up a nice, realistic and cheap SSS shader for human and creature assets. I love the raytraced solid scatter, but with complex models I can’t get rid of some of the artifacts in the SSS channel.
I will post more quite soon.

  • To achieve better results, I like to combine SSS shaders with Vray Mtl shaders which have better solutions for speculars and reflections. With this method the reflection of the surface is controled by BRDF instead of the poor spec control of the SSS shader.

Love Vray's IBL /  by Xuan Prada

When you work for a big VFX or animation studio you usually light your shots with different complex light rigs, often developed by highly talented people.
But when you are working at home or for small studios or doing freelance tasks or whatever else.. you need to simplify your techniques and tray to reach the best quality as you can.

For those reasons, I have to say that I’m switching from Mental Ray to V-Ray.
One of the features that I most love about V-Ray is the awesome dome light to create image based lighting setups.

Let me tell you a couple of thing which make that dome light so great.

  • First of all, the technical setup is incredible simple. Just a few clicks, activate linear workflow, correct the gamma of your textures and choose a nice hdri image.
  • Is kind of quick and simple to reduce the noise generated by the hdri image. Increasing the maximum subdivisions and decreasing the threshold should be enough. Something between 25 to 50 or 100 as max. subdivision should work on common situations. And something like 0.005 is a good value for the threshold.
  • The render time is so fast using raytracing stuff.
  • Even using global illumination the render times are more than good.
  • Displacement, motion blur and that kind of heavy stuff is also welcome.
  • Another thing that I love about the dome light using hdri images is the great quality of the shadows. Usually you don’t need to add direct lights to the scene. If the hdri is good enough you can match the footage really fast and accurately enough.
  • The dome light has some parameters to control de orientation of your hdri image and is quite simple to have a nice preview in the Maya’s viewport.
  • In all the renders that you can see here, you probably realized that I’m using an hdri image with “a lot” of different lighting points, around 12 different lights on the picture. In this example I put a black color on the background and I changed all the lights by white spots. It is a good test to make a better idea of how the dome light treats the direct lighting. And it is great.
  • The natural light is soft and nice.
  • These are some of the key point because I love the VRay’s dome light :)
  • On the other hand, I don’t like doing look-dev with the dome light. Is really really slow, I can’t recommend this light for that kind of tasks.
  • The trick is to turn off your dome light, and create a traditional IBL setup using a sphere and direct lights, or pluging your hdri image to the VRay’s environment and turn on the global illumination.
  • Work there on your shaders and then move on to the dome light again.