The term IES is derived from the Illuminating Engineering Society. This society of lighting engineers researches lighting methods and light distribution, studying how light beams spread from various light sources. We want to know why they are called IES lights. So let’s provide some explanations about the work done in this society. This society works directly with the lighting industry. They determine how different light sources emit their rays. In simpler terms, they determine how light is emitted. Each light source illuminates a space around it. But as you’ve noticed, not all light sources do this in the same way.
Some lights have a higher density at the center of emission, while others have a tighter concentration of rays around them. The Illuminating Engineering Society determines how photons are emitted around a light source and how to measure it. Now, when the lighting industry wants to produce new products, they use the information from this society. For example, suppose a company wants to produce a chandelier. It is important for them that this large chandelier focuses its light on only a part of the environment, or that they want to design a flashlight with a very wide illumination range. In this case, the information produced by the Illuminating Engineering Society will help them.
However, in the world of rendering, the discussion is a bit simpler. Suppose you want to design a scene. In this scene, you use several types of lamps, different light sources, and so on. To accurately simulate these lights and determine the effect of light rays on the surrounding surfaces, you can use the experiences and research of the Illuminating Engineering Society. This society stores its information in files with the IES format. These files contain various information about how photons are emitted, the density of photons in each section, and so on. This information is stored separately for each light source. So you have files that store the behavior of different light sources according to reality. There are also many factories that produce light sources. For example, imagine a factory that produces a new type of neon lamp. This factory provides the light projection specifications of its lamp in the same IES format for other industries and applications. Fortunately, these files are freely downloadable. One of the most famous websites is Lithonia at www.lithonia.com, which allows you to download a large number of IES types. So if you want to use a particular lamp in your project, you can use the IES file of that light to create exactly the same effect in your rendered scene as the real light source creates in nature. As a result, in a nutshell, IES files are simulations of the behavior of light sources in reality.
Now that we understand the concept of IES files, we need to know how to visualize these light sources. Well, if we want to render each of these light sources individually and see the result, it would be an endless story. Consider that there are thousands and thousands of IES files available. We know some of them, but many others are unknown. Therefore, we need to examine IES files before rendering to know what kind of light distribution and ray density each of these files simulates. For this, you can use many tools, including IES Viewer. Many companies have produced IES Viewer software, most of which are free. So you can easily find dozens of such software with a simple search. As you can see in the image, by selecting each IES file in these software, the way photons are emitted and the density of rays are clearly shown.
So, in the first step, you download the desired IES files, then view them using the relevant software, and finally, after selecting the appropriate file, you should use it in your scenes. It should be mentioned here that almost all software and rendering engines can support IES. In fact, the lack of IES support in a software or Render Engine is a sign of the weakness of that engine. Each rendering engine has an option for selecting IES in its lighting settings. For example, in VRay, you should use VRay IES Light, and in Maxwell Render, you should use the IES/EULUMDAT emitter, all of which provide light sources that can use IES. It doesn’t matter which rendering engine you use for your project, what matters is what light sources you use. These light sources should emit their rays based on the IES structure.
Download IES viewer, IES creator, and samples of IES files:
password: eprhino.com
