In 7 Ways to Achieve Realistic Lighting in Blender, Johnson briefly covers IES lights as one of the ways to create more realistic renders. In this article we'll go a bit deeper into the topic of IES lights and how to use it with Blender and Cycles.
What is IES Lighting?
IES is an acronym for Illuminating Engineering Society. The IES file (usually a .ies file) stores directional intensity information of a light source. This file makes it possible to recreate this light in a three-dimensional space. Many of the world’s high profile lighting manufacturers provide IES files for different lighting models they manufacture.
Introduction of IES lighting to Blender
IES lighting was introduced into Blender with the release of Blender 2.80. The IES Texture Node in Blender works perfectly with just the Cycles render engine as at the release of this article. The Blender manual as from Blender 2.80 has full documentation on the input, properties and output of this node. This node is the backbone of photorealistic artificial lighting in Blender. It extends the option for lighting beyond the constraint of just a Point, Sun, Spot and Area lamp.
Blender 2.80 manual, (2020). You can read documentation of the IES Cycles node in Blender here
Cycles Nodes Set-up
Among other lamps, the Point lamp works best with the IES texture node, the Point lamp being a non-directional light source; its directional intensity is easily manipulated to suit its real life representation by the .ies file in the IES texture node. Nodes are only available in the object properties of lamps in the Cycles Render Engine therefore Cycles Render Engine must be selected as the Render engine to activate the Node for the point lamp.
With the Cycles Render Engine selected, the Use Nodes property will be available in the object properties of the point lamp. Select the Use Nodes option to activate the Node properties of the lamp.
Now navigate to the Shader Editor to attach the IES texture node to the Strength property of the Emission Node. In order to locate the IES Texture Node, navigate to the header of the Shader Editor and click the Add icon or use the Shift+A shortcut to add new Node and navigate to Textures then select the IES texture. Now connect the factor of the IES Texture to the strength of the Emission Node. Since we are using a downloaded texture from a lighting manufacturer, we need to select External in the IES Texture Node.
Note: You can download some free IES textures from leomoon.com
Select the folder icon and navigate to the folder with the downloaded IES textures, select the .ies file of your choice. Now the point lamp will illuminate your scene just like the texture imported into the IES texture node. In order to create a more photo-realistic lamp you can decide to add a Blackbody converter. In other to do this you can simply press Shift+A on the keyboard, navigate to the Converter and select Blackbody; connect the color of the Blackbody node to the color of the Emission node. Adjust the temperature of the Blackbody node to suit the real life representation of the lamp or look up the datasheet of manufacturer to input the precise temperature.
Controlling the direction of IES lighting
The Rotation data of the Mapping Node can be used to control the direction of illumination of the point lamp in the scene to get the direction of the light we desire.
Some Implementations of IES Lighting using Blender
These are two renders I did myself where I used IES lights.
3D rendering of falling waters
IES Lighting for a stage setup
I hope you learned something from this article. Leave a comment if you have any questions or feedback!