An IES file (Illuminating Engineering Society file) is a standard text-based file format used in the lighting industry to describe how a light fixture distributes light.

What an IES file contains

• Manufacturer information
• Luminaire (fixture) description
• Lamp details
• Total lumen output
• Photometric data (light intensity at different angles)
• Beam spread and distribution pattern

Why it's used

IES files allow lighting design software to simulate real-world lighting performance accurately in:

• Architectural lighting design
• Interior and exterior lighting planning
• 3D rendering applications
• Energy and compliance calculations

Example Description

An IES file is a photometric data file that defines the light distribution characteristics of a lighting fixture. It contains measured light intensity values and fixture information, enabling lighting design and visualization software to accurately simulate illumination patterns and performance.