What is an IES file?
The .IES file extension most commonly represents an IES Photometric Data File. The Illuminating Engineering Society (IES) created this format to standardize how lighting manufacturers distribute digital light data. These files contain raw ASCII text data that describes the physical light distribution, intensity, and shape of a real-world light source. 3D artists, architects, and engineers use .IES files to simulate accurate, realistic lighting in digital 3D environments.
How to open IES files?
You can open .IES files natively in specialized lighting simulation software like DIALux or Relux. Many 3D rendering engines and animation tools, such as Blender, Autodesk 3ds Max, Unreal Engine, and V-Ray, also support .IES files to create realistic lighting fixtures. Because standard .IES files are text-based (often UTF-8 or ASCII), you can open them in standard text editors like Notepad++ to read the internal metadata and intensity arrays.
File conversion
Sometimes you need to convert photometric data for specific software pipelines. You can use tools on convert.guru to quickly convert .IES files into sensible target formats. For example, users frequently convert .IES files to the European .LDT (Eulumdat) format or extract the data into standard spreadsheets.
Inspect and view IES files online
viewer.online/ies can analyze .IES files to identify the exact format and creator software, inspect the file structure, extract readable text, and check whether an online preview is available. While .IES almost always stores photometric data, file extensions can be misleading. If .IES has multiple possible meanings, we recommend viewer.online/ies to identify the actual format of the user's file. Ultimately, viewer.online/ies is useful for identifying, inspecting, and understanding .IES files without installing software or dealing with compatibility problems.