Introduction


  • This lesson will take you through creating a V-Ray Sun and Sky set up in V-Ray for Maya
  • The information centers around the use of the VRaySun and VRaySky
  • This lesson topic is approximately 30 minutes in length
  • Lesson covers all 3 Learning Cycles for the Lesson Topic – Lecture, Demonstration, and Activity.
  • Learning Outcomes: You will be able to light a scene with a VRaySun and understand how it effects the VRaySky in your 3D scene.


Contents


Overview
Available Materials
Lecture
Demonstration
Activity                                 
Additional resources


Overview


Goal - Create and adjust the VRaySun and Sky. Develop the look for our miniature house set, to create something that has a daytime feel

Objective - We will light a scene with a V-Ray Sun and understand how to get the desired results                                

Outcome - You will be able to adjust the V-Ray Sun Light to create different daytime looks in your renders

 

 


 

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

Sun and Sky is a system to create a daytime look in renders using a sun light and a sky environment

  • Turbidity - The amount of dust in the air and affects the color of the sun and sky
  • Ozone - Tints the color of the sun in an inversely way from Turbidity
  • Horizontal Illumination - The intensity of the illumination on horizontal surfaces coming from the sky
  • Global Illumination (or GI) - The direct (from a light source) and indirect (reflected off surfaces in a scene) illumination that contribute to a physically accurate render


 

2. Image Based Lighting (IBL)


Uses the colors and brightness of an image to illuminate a 3D scene

In a typical V-Ray Sun and Sky setup, the Sky is used as a texture to help illuminate the scene as a GI environment

 

 



 

 

3. V-Ray Sun

a) Overview

  • Developed to work together, the VRaySun and VRaySky reproduce the real-life Sun and Sky environment of the Earth
  • Both are coded so that they change their appearance depending on the direction of the VRaySun’s transform node

 

 

b) Creating daylight

  • To create a VRaySun object, go to the Environment section of the Overrides tab in the Render Settings window
  • The VRayGeoSun node allows you to position the Sun both manually or set to a specific time and/or place on Earth

 

 

 

c) GI and a Physical Camera

  • To see the best results with the V-Ray Sun and Sky, make sure Global Illumination is turned On (bounce engine is not important for this presentation)
  • Adding V-Ray Physical camera Attributes is needed to calculate and expose your renders with Sun and Sky for correct lighting
  • Adjust the F-number and Shutter speed (like on a real camera) to set the overall amount of light that enters the camera lens

 

 

d) Sun Height/Orientation

  • As you rotate the sun light’s Transform node, the Intensity of the light is effected
  • Changes the color of the Sky to set the time of day as sun transform node is rotated

 

 

Sun at 45° (default)

 

Sun at 15°

 

Sun at 90°

 

  • Intensity multiplier – controls the strength of a light
  • Turbidity – the amount of dust in the air and affects the color of the sun and sky
    • Larger values tint the sun and sky yellow or orange (like pollution in a city)
  • Changes the Sun’s contribution to the lighting as the light passes through the air
  • The Intensity multiplier may need to be increased to offset tinting Turbidity creates

 

 

 

Turbidity: 2

 

Turbidity: 3 (default)

 

Turbidity: 10

 

  • Ozone – affects the color of the sun light
    • Value range between 0.0 and 1.0
    • Larger values tint the sun and sky blue
  • Opposite effect than Turbidity

 

 

Ozone: 0

 

Ozone: .35 (default)

 

Ozone: 1

 

 

е) Size multiplier – controls the visible size of the sun as seen by the camera and in reflections
  • Affects the size of the sun in the sky (directly and in reflections)
  • Affects the diffuseness of the shadows (principle of larger sources cast softer shadows)

 

 

Size multiplier 1.0

 

Size multiplier 5.0 (default)

 

Size multiplier 10.0

 

  • Sky model – Determines how the sky distributes the sun’s illumination through the atmosphere
  • Selecting a model depends on the look desired
    • Preetham et al. – the VRaySky procedural texture generated is based on the Preetham et al. method
    • CIE Clear – the VRaySky procedural texture generated is based on the CIE method for a clear sky
    • CIE Overcast – the VRaySky procedural texture is generated based on the CIE method for a cloudy sky

 

 

Size multiplier 1.0

 

CIE Clear

 

CIE Overcast

 

f) Intensity multiplier (with CIE sky models)
  • The Intensity multiplier has much less effect on the illumination when using a CIE model type
  • The (Indirect) Horizontal Illumination parameter is available to help your scene illumination

 

 

Intensity multiplier 0.0

 

Intensity multiplier 1.0 (default)

 

Intensity multiplier 2.0

 

g) Horizontal Illumination – specifies the intensity (in lx) of the illumination on horizontal surfaces coming from the sky

 

 

Horiz Illumination 5,000

 

Horiz Illumination 25,000 (default)

 

Horiz Illumination 60,000

 

h) Filter Color
  • A way to directly tint the hue of the sun light in the scene

 

 

 

Conclusion



 

i) Turbidity and Ozone
  • Effect what’s in the air to tint your scene
j) Intensity and Size Multipliers
  • Not just brightness, but shadow softness too
k) Sky Models                                                                        
  • Horizontal Illumination

 


Demonstration



Time to see it work! 

Watch while I demonstrate how to create and adjust the V-Ray Sun and Sky in our miniature house scene

                                                                                                                                                                             

 

 


Activity



Time to do it yourself!

Now it’s your turn!! Use the provided scene file to recreate the daytime looks as you have seen me demonstrate.
We have also provided a final scene for your reference.

Used values:

  • GI On
  • Physical Camera
    • F-number - 8
    • Shutter speed - 300
  • Sun
    • Intensity multiplier 1.75
    • Turbidity - 5
    • Ozone - .25
    • Size multiplier - 10
    • Filter Color (HSV) - 360, .54, .97
    • Shadow subdivs - 32

 

          

 

Additional resources


Find more training resources listed below: