New and Exciting Features of V-Ray 3.0 - V-Ray render elements & After Effects

Paul Hatton takes a look at V-Ray's render elements and how to composite them into After Effects...

Working with render elements is absolutely essential if you want to adjust your render in post, and add in amazing effects such as exposure adjustments and lens effects. Render elements have been around in V-Ray for ages but they continue to improve their functionality. When saving out your renders it is most beneficial to adopt a high dynamic range format which avoids flattening the image into a compressed range of color values. V-Ray offers support for Deep Images and the OpenEXR 2.2 format and DWA compression. We'll explore in this article how to adopt this workflow and carry out your post production in After Effects.

Why render elements?

Render elements are absolutely essential if you want maximum control to retouch your images in post. They give you a whole host of abilities including specific selections, adjusting specular reflections and even fully re-creating your RGB beauty from a selection of render elements. These elements are particularly useful if you work in a multi-disciplinarian studio where you are required to pass your images onto a re-toucher. They will be eternally grateful if you're able to give them as much information as you can.

Render elements can be viewed through the V-Ray frame buffer. The simple drop-down keeps everything neat and tidy

Gamma and color mapping

If you're going to work with render elements in high dynamic range then you need to make sure that your gamma is set to 2.2 in the 3ds Max preference settings. In the ‘Color mapping' rollout of the render setup make sure the linear workflow is set up with the mode set to ‘None (don't apply anything)'. This will ensure that neither color mapping nor gamma is burned into the image. Perfect!

Here are the required settings for color mapping in V-Ray to ensure that your EXR performs correctly in post production

Creating your elements

With V-Ray selected as your render engine, head over to the ‘Render Setup' dialogue box. F10 for you shortcut loving nerds. Then Select the ‘Render Elements' tab and you'll be confronted with a fairly crude interface. In reality the power is contained in the information you get out of this rather than the complexity of the interface! Click ‘Add…' and select the elements you want. You can select multiple items using Shift or Ctrl.

V-Ray give us access to a whole stack of render elements that we can use to our hearts content

What elements do I want?

The elements that I make regular use of are ‘Global Illumination', ‘Lighting', ‘Reflection', ‘Refraction', ‘Specular' and ‘Wire Color'. These elements give you a good balance of being able to troubleshoot your scenes. An example would be if you're getting render artifacts, then you can quickly diagnose which element the artifact is located on and then narrow down a solution more quickly. The ‘Wire Color' element is good for making selections in post.

V-Ray provide not only the final result render elements but also the raw versions that can be blended together to create the end image

Saving the elements

There are 2 main ways to save your elements. The first is to use the render elements drop-down in the V-Ray Frame Buffer and then the standard save button in the buffer. This isn't ideal especially if you're rendering a series of frames. You are better off using the automatic saving tools in the V-Ray tab and the ‘Frame buffer' rollout. Simply tick ‘Separate render channels' and use the triple-dot button to select the save destination.

Automating the saving of your files makes sense especially if you're rendering out sequences of images

Best format for saving

If you want compressed files then make sure you use something like JPGs or PNGs. Depending on your computer's capabilities and your storage space I would recommend saving out your files to a high dynamic format such as OpenEXR. You can do this by selecting it from the drop-down. It'll give you some options, primarily the choice between a 16-bit or 32-bit image. Most of the time you'll probably find 16-bit images are fine but if you want to guarantee having access to the full range of information in the image then choose 32-bit instead.

If you have the disk space and the software to open it, definitely use the EXR file format

Open EXR 2.2 DWA Compression

V-Ray 3.1 gives us the capability of saving out to version 2.2 of the Open EXR format with the new special DWA compression. This codec was created by Karl Rasche of DreamWorks Animation. This compression format minimizes the loss of quality and yet shrinks the file to a fraction of their lossless size.

V-Ray has continually improved a whole host of features and this is evidence of that

Importing into After Effects

With After Effects, go to ‘Project Settings'. Set the ‘Depth' to '32 bits per channel' or 16 if that's what you saved your EXR out as. Tick ‘Linearize Working Space' and hit okay. This ensures that the colors in your project are managed correctly. Then right-click on your imported file and go to ‘Interpret Footage' and ‘Main'. On the ‘Color Management' tab make sure ‘Preserve RGB' is selected. Your image should now be ready to edit. This process applies to all render elements.

Set After Effects up correctly to be able to handle the EXR files correctly

Post-production in After Effects

With all your render elements imported and set up for the linear workflow, you are ready to make use of their power. For example, why not add an exposure effect and make use of the high dynamic range of your image! Or add the reflection element and paint in the areas that you want stronger reflections with a mask. Alternatively you could layer up the light select elements on top of the GI, reflection and refraction. You could then adjust the color/strength of the individual light select elements. More on this in the next step.

Here you can clearly see especially around the edge of the sofa that if the exposure is dropped by the same amount you still have a lot more color information to work from in the EXR file

V-Ray Light Select Improvements

In version 3 of V-Ray they have further improved their VRayLightSelect element. This element in essence lets you render out the light contribution of either one or more specific lights in your scene. This element is great for making adjustments to your lighting when there's no time to go back and render the final image! In version 3, V-Ray have enabled us to further split the lighting contribution into normal, raw, diffuse and specular.

Splitting the V-Ray light select element into the more specific components give the flexibility to further edit the lighting contribution in post

Top Tip 1: Use one EXR file for all elements

When you choose the EXR file format upon saving you'll notice that the dialogue box allows you to add render elements to the EXR. This basically collates all of the render elements into one single EXR file which makes the process beautifully concise.

Add your render elements into a single EXR file for ease of use later on

Top Tip 2: Recreating your image from elements

To recreate your image from elements you need to render out all the individual elements such as reflection, refraction, lighting and GI to name the most basic ones. Stack these all up in your composition and set their blending mode to add. You should see your beauty render appear before your eyes!

With all your elements saved out, bring them into After Effects and set their blending mode to add. Voila!

Previous chapters

New and exciting features of V-Ray 3.0
V-Ray 3.0: New Features: New and Improved Shaders
V-Ray 3.0: New Features: V-Ray RT explained
V-Ray 3.0: New Features: Interface and Frame Buffer
V-Ray 3.0: New Features - Faster Rendering
V-Ray 3.0 New Features: A guide to the V-Ray clipper
V-Ray 3.0 New Features: V-Ray Hair & Fur

Related links

Check out Paul's website
Take a closer look at V-Ray for 3ds Max
Grab a copy of 3ds Max Projects