Reality and IES a tutorial written by sigstan -
An IES file is the measurement of distribution of light (intensity) stored in ASCII format. IES profiles are useful for creating life-like lighting, as they can represent the physical distribution of light from any light source.
Any of these profiles can be attached to a mesh light in Reality, and this will make the light behave according to the IES profile. Yes, that means you can turn a little mesh light plane into a round spotlight with a well-defined light cone!
IES profiles make this possible to control the light cones and light spill to a degree that is not possible using standard mesh lights and it will take your renders to the next level.
In the tutorial, I show how to make a rather simplistic (primitive-only) simulation of a flashlight in an otherwise low-light scene with a bunch of low-emissive light sources. All to demonstrate the amount of control you can achieve with IES profiles:
As a bonus, he also shows how to create the in-air visible light beam shown using a render effective localized fog/dust volume.
You can find the Reality and IES mini tutorial iin the Official Reality Forums http://preta3d.com/forums/viewtopic.php?f=23&t=692&p=5348#p5348
We would love to see what you have created from this tutorial :) http://ow.ly/d/5GjQ http://ow.ly/i/pY41a