lightBulb 
Generate rapidly a visible glowing light source with its light beam for Vircadia,
using this application.
Once generated, you can adjust the shape, setup the color and userdata and the script will manage the material
and the light entity with no impact on the server since it's all localy rendered for each visitor.
To install:
Here's the url of the script to run the application : https://aleziakurdis.github.io/lightBulb/app-lightBulb.js
(To install in "Vircadia" or "Overte" interface, go in menu: Edit > Running Scripts... Load scripts from url)
You can also create a light bulb by importing a json:
Import using the “Create” application function: “Import Entities (.json) From a URL”
Enter this URL: https://aleziakurdis.github.io/lightBulb/LIGHT_BULB.json
Setup:
Light color: Set the "color" property of the Shape entity, it will determine the color of the light.
Light Intensity: Set the userdata "lightIntensity" parameter
Light beam opening angle: Set the userdata "lightSpotCutOff parameter
Light range: Set the userdata "lightRange" parameter
Restart the client script to have the change effective.
Rotate and position the shape and the light will follow.