You are viewing an old version of this page. View the current version.

Compare with Current View Page History

« Previous Version 17 Current »

     

Introduction


  • This lesson will take you through using V-Ray Object Properties in V-Ray for Maya
  • The information centers around V-Ray Object Properties and their attributes
  • This 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                                 
Additional resources

 


Overview


Goal - In this lesson you will learn how to use the V-Ray Object Properties to control different aspects of the rendering on a per-object basis.

Objective – We will incorporate the V-Ray Object Properties into our 3D scene to take advantage of different ways of overriding render properties        
Outcome – You will be able to apply many of the available Object Properties to objects in our scene and understand how to create special overrides with them. You will also understand how to use V-Ray Object Properties to further control your renders for optimal effect and efficiency

 


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 are some terms to be aware of when thinking about Object Properties and render overrides in general

  • Object ID
    • A way to identify an object or group of objects that can be referenced in Render Elements for separating out for more compositing control
  • Matte Surfaces
    • Turning objects or their materials into holdout objects to have them excluded from the render by rendering them flat black in their place for compositing and other uses
  • Exclusion Lists
    • A way to group objects together to have them be hidden from (or singled out for) reflections or refractions in/of objects in the scene

  

2. VRayObjectProperties


a) Overview

  • VROPs can be assigned directly to geometry nodes for additional control
  • Used to specify additional object attributes and V-Ray render functions on a per object basis
    • Visibility, GI calculation overrides, Shadow Receiving/Casting, etc.
    • To add this node to selected object(s), use the command Apply Single (or Multiple) object properties node from the Create > V-Ray menu or the V-Ray shelf
  • Additional Surface Properties
    • Settings used to manipulate GI and Caustic characteristics
  • Matte Properties
    • Settings used to create hold outs in your renders

 


b) Object ID
  • Used in conjunction with the Multi Matte Render Element
  • Allows single objects (or groups of objects) to have an ID number that can be rendered on separate color channels in a matte pass such as this

 


c) Use Material IDs instead of Object IDs
  • Applied to all objects that have that material assigned to use
  • Check Use Material IDs check box when using this workflow

 


d) Additional Surface Properties
  • Generate or Receive GI Multipliers
  • Controls whether or not the object will generate or receive indirect illumination
  • Controls how much influence is generated for the indirect lighting using the GI Multiplier (Mult.) sliders

 

 

Generate GI Mult: 1
Receive GI Mult: 1

 

Generate GI Mult: 1
Receive GI Mult: 0

 

Generate GI Mult: 0
Receive GI Mult: 1

 

 e) Visibility Options

  • Visible to GI
    • When Off, object(s) will be transparent to GI rays
  • Primary Visibility
    • When Off, object(s) will be transparent to camera rays and will not render in the camera, but may still affect reflections, refractions, and shadows
  • Casts/Receive Shadows
    • When Off, object(s) will be transparent to shadow rays

 


All example renders use VROPs on Palm_Trees group.

Visible to GI: Off 
(GI RE – notice no bounce from trees on the sand)

Primary Visibility: Off

Casts & Receive Shadows: Off

 

f) Matte Properties
  • Uses V-Ray matte system at the object level as opposed to the VRayMtlWrapper that works at the material level
  • Checking Matte Surface means the object will not be directly visible in the scene; the background color (or texture) will be shown in its place instead
  • The object will still appear normally in reflections and refractions and will generate indirect illumination based on its actual material

All example renders on slide use VROPs on luggage (& guitar) and Surf(s)board groups

Matte Surface: On 
(Env_Background.jpg seen in holdout)

Affect Alpha: On
Alpha Contribution: 1

Affect Alpha: On
Alpha Contribution: -1 

 

g) Exclude lists
  • Creates a Maya set called a vrayExcludeList in the Outliner that objects can be added to so they will be seen or hidden from reflections and/or refractions
  • As Include List reverses the affect to make only objects in list seen in reflections and/or refractions

 

 

 

 

 

No Exclusions made to reflections in car

Use Reflection Exclude List: On
Palm_Trees group added to List

Use Reflection Exclude List: On
As Include List: On

 

h) Object Properties vs. Mesh Properties
  • Don’t forget about the extra V-Ray Attributes that can also be added to the shape node of your objects
  • Adding any of these sets will give you more customization to your V-Ray render setup allowing you to further control subdivisions and displacements, for example

 

 


Conclusion



a) Object ID

Separate objects out to have more control compositing with Multi Matte Render Elements

b) Matte Surfaces

Making our objects a holdout with the background for easier compositing

c) Exclusion Lists               

More flexibility in how objects are seen in reflections and refractions

Demonstration



Time to see it work! 

Watch while I demonstrate how to create and adjust V-Ray Object Properties in our scene to control how we can compose and adjust the image back together.

          

 

Activity



Time to do it yourself!

Now it’s your turn!! Use the provided scene file to better understand V-Ray Object Properties as you render a scene.
We have also provided a final scene for your reference.

 

  

Dialing in the right values:

  • VROP_Sea
    • Includes Sea geo
    • Not Visible to GI, Does not Cast or Receive Shadows
  • VROP_tress
    • Includes Plam_Trees group
  • VROP_luggage
    • Includes Surfs (boards) & Luggage groups
  • VROP_car
    • Includes Wheels, Exterior, & Interior groups for car geo
  • vrayReflectionExcludeList1
    • Drag and drop Palm_Trees group to add to List

 

All Object Properties in demo are adjusted on & off depending on the property being shown.

 

         

Additional resources


Find more training resources listed below: