Introduction


 

  • This lesson will take you through creating and using V-Ray Advanced Render Elements for compositing back to Beauty
  • This information centers around the Render Elements you can create using V-Ray
  • The lesson topic is approximately 30 minutes in length
  • Lesson covers all 3 Learning Cycles for the Lesson Topic – Lecture, Demonstration, and Activity

 

Contents


Overview
Available Materials
Lecture
Demonstration   
Activity
                                                                                                                

 

Overview


 

Goal - By the end of the lesson you will have a complete understanding on how to use Raw Render Elements to fine tune your renderings in post production

Objective – We will render several Raw Render Elements and use them to create an advanced beauty pass for even more control in compositing                          

Outcome – You will understand how to separate your renders into Render Elements to produce a professionally composited image

 

Available materials


To set up the lesson follow the links below and download all available materials.

Lesson plan download
Presentation (Lecture) download
Demonstration tutorial download                                                               

Scenes & Assets download
 


Lecture


1. Terminology

 Here’s some terms to be aware of when thinking about Render Elements.

  • Pass
    • A “once-over” on the rendering to produce a specific effect. You can think of a pass as a “sweep” through the image to do one specific thing.
  • Render pass
    • A pass that renders the entire image and stores one or more elements of the scene, for example just the lighting or just the reflections
  • Render Element
    • The results of a render pass that can be combined in a post process to adjust the final image
  • Compositing
    • The combining and adjustment of Render Elements and/or other elements such as live footage or background plates
  • Beauty pass
    • The combining and editing of certain Render Elements to create a traditional rendered image

 

2. V-Ray Render Elements


For a high-end work such as feature films, rendering straight out of Maya/V-Ray is usually never enough control to get the desired look:
  • Rendered image might need adjustment to match live-action lighting, color temperature, etc.
  • Director might want to try different sky backgrounds, combinations of landscape elements, etc.
  • Common adjustments include color correction, improvement of contrast, adding or enhancing Lens Effects
  • Making changes to Render Elements is faster and easier than re-rendering

 

 



 


 



 


 Compositing with Render Elements provides the solution

  • Render Elements layered on top of one another to generate final image
  • Render Elements can be adjusted individually to produce and refine a certain look
 
Compositing of Render Elements is done outside Maya/V-Ray, in a compositing program
  • Software programs designed for compositing include After Effects, Nuke, Fusion, Photoshop
  • Render Elements are exported from V-Ray and imported into compositing software

 

 



 


 



 

 

A Render Element is a regular 2D image, where each pixel has RGB numerical values
  • 3D model and parameters are not exported, just an image!

 In compositing, each Render Element is usually “added” or “multiplied” with previous layers

  • In compositing, black = 0 and white = 1
  • Colored pixel + black pixel = no change
  • Colored pixel + white pixel = brighter colored pixel (up to pure white pixel)
  • Colored pixel x black pixel = black pixel
  • Colored pixel x white pixel = no change

All Render Elements can be exported together in one multi-channel EXR file, or…
 
Each Render Element can be saved in its own image file for layering in compositing software

 

 



 


 



 

 

a) Render Elements Compositing Workflow
  • Add Render Elements in Render Settings window
    • Once added, elements automatically available in VFB for each rendered image
    • Save as EXR file for compositing
    • EXR file is a collection of Render Elements (2D images)
  • Composite Render Elements in programs like After Effects
    • Using plugins, multi-channel EXR files open as layers, one layer per Render Element
    • Render Elements can be adjusted to create different effects
    • Render beauty pass as final image
  • Raw Render Elements Export
    • In order to properly export the “Raw” and “Filter” elements the original render element must be exported as well
    • GI render element is needed for Raw GI and Diffuse render elements
    • Lighting render element is needed for Raw Light and Diffuse render elements
    • Reflection render element is needed for Raw Reflection and Reflection Filter render elements
    • Refraction render element is needed for Raw Refraction and Refraction Filter render elements

 

 


b) Atmosphere Render Element

  • Atmospheric effects such as fog
  • Render element can be used to punch up or tone down fog effect in beauty render

 

 

Atmosphere Render Element

Beauty Render

 


c) Background Render Element
  • Just the background as viewed behind solid objects
  • Used for color correction on background alone

 

 

Background Render Element

Beauty Render

 


d) Diffuse Render Element
  • Contains the diffuse surface color (not affected by lights)
  • Base color that all the other passes affect

 

 

Diffuse Render Element

Beauty Render

 

 

e) Raw Lighting Render Element
  • The amount of diffuse direct illumination before it's multiplied by the surface’s material
    • Basic Lighting pass is Diffuse * Raw Lighting
  • An object material surface properties attenuate the raw light through the reflection, refraction, SSS, etc.

 

 

Raw Lighting Render Element

Beauty Render

 


f) Raw Global Illumination Render Element
  • The Global Illumination’s lighting contribution to the scene
    • Basic GI pass is Diffuse * Raw GI
  • Only present if Global Illumination is Enabled

 

 

Raw GI Render Element

Beauty Render

 


g) Raw Reflection Render Element
  • The pure surface reflection as if the surface is 100% reflective
  • Multiplied with Reflection Filter to produce complete Reflection information

 

 

Raw Reflection Render Element

Beauty Render

 


h) Reflection Filter Render Element
  • The greyscale information used to multiply with the raw reflection element to give the final surface reflection
  • Greyscale values take into account things such as Fresnel, material’s actual reflectivity amount, etc.

 

 

Reflection Filter Render Element

Beauty Render

 


i) Combining Reflection Render Elements
  • Multiplying the Raw Reflection and the Reflection Filter passes creates the Reflection pass

 

Raw Reflection Render Element

Reflection Filter Render Element

Reflection Render

 

j) Specular Render Element
  • Specular highlights only
  • Use this element to punch up or tone down specular highlights
  • Example: Brighten specular highlights to give impression of very bright lights off screen

 

 

Specular Render Element

Beauty Render

 


k) Raw Refraction Render Element
  • The pure surface refraction as it if the surface is 100% refractive
  • Multiplied with Refraction Filter to produce complete Refraction information

 

 

Raw Refraction Render Element

Beauty Render

 


l) Refraction Filter Render Element
  • The color information used to multiple with the raw refractions to give the final surface refraction
  • Greyscale values take into account things such as material’s actual refractivity

 

 

Refraction Filter Render Element

Beauty Render

 


m) Combining Refraction Render Elements
  • Multiplying the Raw Refraction and the Refraction Filter passes creates the Refraction pass

 

Raw Refraction Render Element

Refraction Filter Render Element

Refraction Render

 

n) Saving the render elements
  • Use the save button in the VFB toolbar
  • Saves directly to an OpenEXR file containing all Render Elements specified in Render Settings
  • Can also save each elements individually into image files

 

 

 


o) Advanced Beauty Compositing Formula


Background       +

  Diffuse         х

(           Raw Light

+              Raw GI          )

+              Specular

 


+       (   Raw Reflection

х          Reflection Filter        )

+          (    Raw Refraction

x         Refraction Filter    )

+             Atmosphere

 

Conclusion



а) Render Elements
  • Gives you the ability to adjust the rendering without re-rendering
b) Raw Pass
  • Pure surface information before altered by Filter Pass
c) Filter Pass
  • Acts an alpha channel for the Raw Pass

d) Beauty Compositing Formula                                                                                                                                                                                                                                            

  • Background + Diffuse * (Raw Light + Raw GI) + (Raw Reflection * Reflection Filter) + Specular + (Raw Refraction * Refraction Filter) + [SSS] + [Self Illumination] + Atmosphere


Demonstration



Time to see it work! 

Watch while I demonstrate how to set up and save Render Elements

 

    

                      


Activity



Time to do it yourself!

Use the provided scene file to set up and save Render Elements

Practice Workflow

  • Choose Render Elements in Render Settings window
  • Render to VFB
  • Look at Render Elements                                                            
  • Save to EXR file