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# V-Ray Sphere Light

## Introduction

• This lesson will take you through creating a Sphere light in V-Ray for Maya
• The information centers around the use of the VRayLightSphere
• This lesson topic is approximately 20 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 VRayLightSphere and understand how to adjust the settings to create the look you want in your renders.

## Contents

Overview
Available Materials
Lecture

## Overview

Goal - You will learn how to use the different settings of the V-Ray Sphere Light in order to achieve different results

Objective - We will light a scene with the V-Ray Sphere Light and how to adjust to get the desired results

Outcome - You will be able to adjust the V-Ray Sphere Light to create different high-quality looks to your renders

## Lecture

### 1. Terminology

Lighting is important to our lives and in our 3D scenes. Without it we can’t see anything!

• Intensity - How strong the light will be in the scene
• Color Temperature -
• A real-world measurement of the hue of a light
• Cool means in the blue/cyan range
• Warm means in the yellow/orange range
• Units - Measurement types used to make the light physically accurate to real world measurements

### 2. Light

a) Lighting in the real world

• Controlling the direction of a light
• Larger lights will have softer (more diffused) shadows

b) Light Falloff

• Real lights have Decay
• Light falls off to the square of it’s distance – Inverse Square Law.
• An object at 2x the distance away from a light will receive 1/4x of the light it would at 1x distance
• An object at 3x the distance away from a light will received 1/9x of the light it would at 1x the distance

c) Light Temperature

• Use the temperature value to create the right mood for your scene

### 3. Sphere Light

a) Light Overview

• Intensity is the overall strength of a light
• The Units selected will affect if the amount of light emitted by the V-Ray light changes due to the light’s size or remains constant regardless of size of the light
• Its preferable to adjust the Radius over scaling the light up and down
• Color vs. Temperaturе
• Which mode to use depends on what results you want
• Sphere segments
• controls the quality of the light object when it is visible either directly or in reflections

b) Intensity, Color, Temperature

• Mode: Color - the light’s color is directly specified by the Color value. When using photometric units, this color is normalized so that only the color hue is used.
• Mode: Temperature - specifies the light color temperature in degrees Kelvin
• Great for matching real world lights
• Intensity Multiplier - defines the intensity of the light in terms of the units chosen in the Units parameter.

Color Mode: Color (with purple Light Color)

Color Mode: Temperature (with Temp. of 4500)

c) Units - Using correct units is essential when you are using the VRayPhysicalCamera. The light will automatically take the scene units scale into consideration to produce the correct result for the scale you are working with. The possible values are:

• Image (default) - the color and multiplier directly determine the visible color of the light without any conversion.
• Lumious power (Lumens) - total emitted visible light power measured in lumens. When selected, the intensity of the light will not depend on its size. A typical 100W electric bulb emits about 1500 lumens of light.
• Luminance (lm/m/m/sr) - visible light surface power measured in lumens per square meter per steradian. When selected, the intensity of the light depends on its size.
• Radiant power (Watts) - total emitted visible light power measured in watts. When selected, the intensity of the light does not depend on its size. This is not the same as the electric power consumed by a light bulb for example. A typical 100W light bulb only emits between 2 and 3 watts of visible light.
• Radiance (w/m/m/sr) - visible light surface power measured in watts per square meter per steradian. When selected, the intensity of the light depends on its size.

e) Sphere segments - Smooths out the look of the object when visible in the scene, both directly and within reflections

f) Options
• No decay – light intensity is inversely proportional to the square of the distance from the light (objects farther from light are darker). This option removes that property making the intensity consistent forever
• Invisible – controls whether the rectLight source itself is visible in renders

## Conclusion

а) Intensity Multiplier

• Controls how bright the light is

b) Color Temperature

• Sets the hue of the light with Kelvin temperatures

c) Units

• Adjusts how the light works within the scene

## Demonstration

Time to see it work!

Watch while I demonstrate how to create and adjust a Sphere Light in our miniature house scene.

## Activity

Time to do it yourself!

Use the provided  scene file to recreate the cinematic look as you have seen me demonstrate.

Dialing in the right values

a) Sphere Light – In Wall Lamp

• Temperature 7,000
• Intensity multiplier 250
• Lumens Units

b) Sphere Light – In Desk Lamp
• Temperature 2,800
• Intensity multiplier 500
• Lumens Units