.LDT File Extension

Eulumdat Formatted Luminaire Data File

Developer DIAL
3.3  |  15 Votes

What is an LDT file?

An LDT file is a luminaire (light fixture) data file created for use with DIALux, a professional lighting planning application. It defines the lighting parameters of a luminaire, including its number of lamps, light intensity, light distribution curve, and size.

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Screenshot of a .ldt file in DIALux LDT Editor
LDT file open in DIALux LDT Editor

Each LDT file contains plain text data that defines a luminaire's features. This data is saved in the Elumudat format, which was created by DIAL for use in DIALux. Lighting designers can import LDT files into DIALux to include them in lighting plans for homes, office buildings, neighborhoods, commercial sites, and other environments.

Typically, lighting professionals and others create LDT files using LDT Editor, a free LDT file creator also provided by DIAL.

How to open an LDT file

You can open an LDT file in DIAL LDT Editor (Windows) or Meduza Photometric Toolset (Windows) to view the luminaire data it contains in a standardized format. You can also import LDT files into DIAL DIALux Evo (Windows) to simulate a lighting source.

Opening an LDT file in a text editor

LDT file open in Microsoft Notepad
LDT file open in Microsoft Notepad

Alternatively, you can open an LDT file in Microsoft Notepad, Apple TextEdit, or any other text editor, to view the plain text data it contains. However, it's far better to open an LDT file in LDT Editor or another program that shows the file's data in an understandable format.

How to convert an LDT file

You can use the PhotoView module included in OxyTech LITESTAR 4D Open to convert LDT files to the following formats:

  • .IES - IES Photometric Data
  • .LTL - Luminaire Data
  • CIE - International Commission on Illumination Data

You can use the online Eulumdat Tools ELUMDAT to IES Converter to convert LDT files to the IES format.

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Programs that open or reference LDT files

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The FileInfo.com team has independently researched the Eulumdat Formatted Luminaire Data file format and Mac, Windows, and Linux apps listed on this page. Our goal is 100% accuracy and we only publish information about file types that we have verified.

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