Skip a Trip to Photoshop: Use the V-Ray Color Correction Node

V-Ray for Maya has some pretty handy (but slightly hidden) tools that can be added from the Create From V-Ray Plug-in menu and one of the best is the Color Correction node. It’s basically a grading dialog for textures and can do quite a bit, and it can save you trips to Photoshop to just do slight tweaks to hue, contrast, etc.:

The only thing to keep in mind is that the brightness is a gain slider, not a gamma-based correction, so it should be avoided to adjust mid-tones. Also, you can try out the other Color Correct plug-in for yourself but it’s less full-featured than the Color Correction plug-in. Why they are so similarly named is a question for the sages.

Small Maintenance Update to V-Ray Tuner for Maya 2014

V-Ray Tuner 3.4.1 posted for download. There’s not too much new here but there’s an important fix for the Optimize button script for Maya 2014. Maya 2014 has a bug that returns the wrong number for RAM amount for “memory -phy” so, if you’re running 2014, the script asks you to enter your memory amount in GB. Otherwise, the only other new addition is that I’ve added Point Light support to per-light render script.

V-Ray Tuner 3.4 Update Releasededed

This is not a huge update to V-Ray Tuner but it brings a few fixes and features that affect various things. Here’s 3.4 changelog:

• Composite pre-bake diffuse colour with V-Ray Dirt RE:

• Changed DaveBake420 10% value to be 512x512, instead of 409.6x409.6 (10% of 4096).
• Attach Cam button now prompts you to add and enable physical cam attributes if you don’t have them already on the selected camera. If you select no, it will still hook up the overscan setting.
• materialDropper and materialCopyDropper now work on face-level selections as well as with objects.
• Optimize button now sets memory setting (sys_rayc_dynMemLimit) to 80% of total memory in your system.
• Fixed material worker layer script. I had started to implement a new feature but forgot to finish it so it was broken for a couple versions.
• Per-light render script now does solo light re-renders. If you have a light selected and run per-light render, it will only render that selected light:

• Small fix to per light exposure light tweak - it could fail to properly detect your light selection before.
• Revert To Saved Document script added to Utils menu.

V-Ray Tuner 3.3 Gets the Hot Feature Injection

I am pretty happy with the latest V-Ray Tuner 3.3 update. It adds a number of features that I now use constantly and I think they’ll be pretty popular. Here’s a break down of what’s new in 3.3:

• Optimize setting now prompts you for core count when distributed rendering is on. Use the max threads of any of your machines that are active in the render. If you have a local machine that’s eight cores (or four hyperthreaded) and a slave machine that has 16-cores hyperthreaded (32-threads), enter 32. Disable DR and click Optimize again and it will properly set the thread count for the local machine only:

• Added a disable texture filtering script to Materials menu so you can turn off filtering for File nodes all at once.
• DaveBake420 script has got a big uprade in 3.3. Now has an option to comp your Dirt V-Ray pass with the diffuse channel after baking. Good for adding grittiness to diffuse textures with little work:

• Fix Light Size button replaced with create Sun & Sky script. V-Ray no longer has issues with manually-scaled lights so the script is no longer necessary.
• Sprite Maker script now works with currently selected camera, not just main persp camera.
• New Material Swapper script that should replace the “Maya and mental ray Mat to VRay” script for conversion of Maya materials to V-Ray mats and back. Paul Dreisen graciously provided the original script but I tend to convert more between Maya’s materials and V-Ray than mental ray mats and I wanted to beef up the accuracy of conversion that’s done by the script to save time. This script does a really good job of converting things like Phong materials from Mudbox FBX files to V-Ray, with all channel-mapped texture intact. If you want to go back to Mudbox but you’ve set up a V-Ray Material, it will swap the V-Ray Mat for a similarly set-up Phong, Lambert or Blinn mat. It’s also great for mass-converting Paint Effects polygon materials. Here it is in action:

It’s not shown in that video but the release script now has a palette with an option to keep the original swapped-out mats after conversion.

As always, let me know if there’s anything you want added or tweaked in V-Ray Tuner.

Amazing Python Script for Nuke That Creates a 3D Camera from a V-Ray EXR Image

If you do compositing in Nuke, you know it can be annoying to get camera data in and out of a 3D package like Maya or Max. Imported camera data quickly gets outdated when new frames are rendered, which forces you to jump back and forth between your 3D app and Nuke. Fortunately, yesterday I discovered a script for Nuke that makes it dead simple to generate camera data from the camera metadata embedded in V-Ray’s EXR-rendered images. After installing the Python script as a menu item, just select a V-Ray EXR render and the script will make a camera node that you can plug into a 3D scene template. It’s amazing:

It even works with animations, meaning you never have to jump back to your 3D app to get new camera data – just kick out a new camera node for the newer EXR frames.

So, here is how you install it. Grab the Python code from the Pastebin site here. Paste it to a new plain text file in your Nuke scripts folder. In OS X and Linux, that’s ~/.nuke/ (where ~/ is your home folder). OS X users can make short work of it by doing this in the terminal after copying the code:

pbpaste > ~/.nuke/createExrCamVray.py

pbpaste is a command line version of a pasteboard paste command in OS X (pbcopy does a copy if you want to pipe to the clipboard). Next, add the call to the script to your Nuke menu bar by adding these lines to the end of Nuke’s menu.py file (For me, it’s located in /Applications/Nuke6.3v4/Nuke6.3v4.app/Contents/MacOS/plugins/menu.py):

import createExrCamVray
m = menubar.addMenu("V-Ray")
m.addCommand("Create Camera from EXR", "createExrCamVray.createExrCamVray()")

The code is wrapping on my blog site, so it’s better to grab it from this text file. Then, once you relaunch Nuke, you’ll be set up.

Mixing a V-Ray Sun and Sky Environment with HDR Environment Light Image

For a while now, I’ve been mixing V-Ray skies with some HDR environments and was doing it in Nuke because I didn’t realize it was doable in Maya – that is, until Vlado at Chaos Group suggested using a Blend Colors utility. I should have thought of it myself but sometimes you forget just how good V-Ray integration is within Maya, and assume something like that won’t work. But it does, so here is a quick rundown of how to mix V-Ray sun/sky environment with a HDR Environment Light Image:

The only trick to this workflow, as shown in the video above, is to disconnect one of the sun/sky environment connections in the Render Settings dialog and then create a file node for the HDR. This ensures that V-Ray will make the proper VRayPlaceEnvTex spherical UV projection. You could do this manually but it’s just easier to have V-Ray do it automatically when connecting it to the environment slot. Then you make a Blend Colors utility, drop the file node and the sky into the two slots and then MMB-drag the Blend Colors utility into the Environement slots. If you would rather have the lights in your IBL added to your sky, use an +/- Average utility to have the IBL pixels added to the sky instead of linearly blended. Make two Input 3D connections (the 3D in this context is not XYZ, it’s RGB) and then connect the sky and file nodes to the inputs in the Hypergraph or Node Editor:

Then you will have a bright sky and added IBL highlights:

Rendering and Compositing a Dust Pass in Maya

I’m doing a quick render to use as the base for a painting and wanted to add some dust to my scene to cover the rubble and earthquake. It’s all pretty draft quality work but notice how quickly a dust layer comped in Photoshop adds a lot of realism to a pretty sparse scene:

The process is pretty easy: duplicate your render layer with everything in it, create a render layer override that sets all your objects to your Lambertian dust material and render. Then you bring it into Photoshop or Nuke and paint in the dust. Add a material ID pass to make object masking easier and you’ve got a great little workflow. Since dust and snow can gather to look a lot like ambient occlusion, you can try using an ambient occlusion pass as a mask while painting in your dust layer:

V-Ray Tuner 3.2 – Small Maintenance Update for Linear Workflow Tools

I’ve updated V-Ray Tuner with some more robust changes to the handling of materials and textures when using the Gamma Correct Me script. It now works with any type of texture and it no longer gamma corrects a node if it’s parented to a gamma correct already. It’s more foolproof overall and, as always you can do the degamma on textures or the parent V-Ray materials:

Other additions:

• Edit all selected images script to open all selected file nodes in image editor
• Shellac me now enables shadows for both base and coat materials. I always use this, so if you don’t want this on, remove these two lines from the script: setAttr ($currentSurfaceShader[0] + “.bumpShadows”) 1; and this: setAttr ($fresnelCoater + “.bumpShadows”) 1;

My MakeHuman V-Ray SSS Skin Conversion Templates

So, after some tweaks and playing around, I’ve come up with a good starting set of templates to convert MakeHuman output characters to V-Ray for Maya via Nuke. Download the setup files at the bottom of this page (includes Maya V-Ray scene and source images as well). Currently, the Nuke template that I use for the source skin is set up for the caucasian skin PNG files that come with MakeHuman. I tried using it for the Indian-looking skin and it is far too red, but I’m sure someone could quickly get it working with different skin types. That is the advantage to this procedural Nuke template: it requires little work to make variations, unlike a series of Photoshop edits, which would be tricky to do for things like cloning and brushing of the lips. I realize not every uses Nuke for image edits but it’s great for stuff like this and I’m just making my work available to you. So, this is how it works: you take your single input PNG file and plug it into the starting point file input of the Nuke template (click for high res):

The Nuke script then splits up the single RGB input and does the appropriate edits and output for all elements of a V-Ray FastSSS2 map. How good is it? Well, I’m not an expert on skin and SSS but it’s a good start, in my opinion. The source MakeHuman PNG:

The Nuke template has two options for types of image input. If you’ve edited the texture in Mudbox or Mari and used 32-bit mode for the textures, use the linear gamma file input.

Here’s a render in Maya of the caucasian female skin PNG conversion:

It’s using a V-Ray Fresnel Blend Mat setup, so if you want to use it as a template for other work, go ahead. It’s free for use in commercial work. It could still use some tweaks for the lips and the only real problem with this setup is that the bump map can’t be used because of the texture map seams, so it looks a little too uniform. That’s also a fault of the actual texture, which doesn’t have any vein touches or pores – this isn’t meant to be feature actor material, just background figure quality. I left the bump stuff in the template files since I thought you might find it useful to see how it’s done and if you want to make a seamless fix for yourself. The Nuke scene includes a 3D reference model so you can check for seams in a 3D viewport while working on the textures. I’ll work on it eventually and post the revised work here. This is very much a work in progress and this is the 1.0 release of this package.

Download: MakeHuman Maya and Nuke template files v1.0

Just a note that the model is nude, since I was checking for seams. You might not want to freak out your guests by opening an unclothed tween on your screen.

V-Ray Tuner 3.1 Adds Basic File Texture Manager and Other Features

Updated V-Ray Tuner with some things I think many people will find helpful:

• Select objects with selected materials script selects objects, not just faces, for selected material:

• Added feature to Material Copy Dropper: if only one object is selected, it will duplicate the material and upstream nodes and apply it to the selected object
• Gamma Correct Me now gamma corrects connected subtextures as well as swatches for V-Ray Materials:

• Gamma Correct Me dialog automatically selects the menu item for the item type you selected: file or V-Ray Mat
• Added Gamma Correct Me support for VRayFastSSS2 mat. Works for both swatches and attached file nodes
• Added per-light exposure tweak support for V-Ray Light Materials, V-Ray Materials (self-illum slot is adjusted by exposure), Sun and Environment (Sky).
• Added script to select and copy files that are outside project sourceimages folder to sourceimages and relink them:

Download link. Enjoy.

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