Free online LDT to PDF converter

Lighting-design software often creates LDT files, while PDF is required for sharing photometric data, attaching reports, or archiving a fixed version. The conversion method depends on whether you need the LDT source rendered as readable text or turned into a proper lighting report with diagrams.

What the LDT format is

LDT usually means an EULUMDAT photometric file used to describe a luminaire’s light distribution. It stores structured plain text containing information such as the manufacturer, luminaire dimensions, lamp data, luminous flux, and candela measurements at defined angles.

Lighting manufacturers and programs such as DIALux evo, Relux, and other photometric design tools create or import LDT files. You may encounter one in a luminaire library, a lighting calculation project, or a manufacturer’s downloadable technical data.

What the PDF format is

PDF preserves page layout, fonts, tables, and graphics across operating systems. It is suitable for emailing, printing, submitting lighting documentation, and archiving a report that should not change when opened on another computer.

A PDF does not inherently preserve the editable photometric structure of an LDT file. It normally contains a visual representation of the data, while the original .ldt file should be retained for later calculations.

How to actually convert LDT to PDF

Use the online converter

1. Open the LDT-to-PDF converter on 101convert.com.
2. Upload the .ldt file.
3. Choose PDF as the output format and start the conversion.
4. Download the generated .pdf file and open it to check that the text, tables, and page layout are complete.

This method requires no installed software and is suitable when the required result is a readable PDF representation. Do not upload confidential manufacturer data or project information unless the file-handling policy permits online processing.

Create a proper lighting report with desktop software

1. Install DIALux evo or Relux from the vendor’s official distribution.
2. Import the luminaire file using the program’s luminaire or photometric-file import function.
3. Check the imported manufacturer name, dimensions, luminous flux, and photometric distribution.
4. Generate the program’s documentation or luminaire report.
5. Use the report’s Export → PDF or Print → Save as PDF function.

This produces a more useful result than simply printing the raw file because the PDF can include polar curves, tables, luminaire images, and calculated lighting results. Menu names differ between software versions.

Save the raw LDT contents as a PDF

For a basic text copy, open the file in a text editor, select File → Print, and choose a PDF printer such as Microsoft Print to PDF or a system PDF export. This preserves the source values as text but does not generate lighting curves or a professional photometric report.

Quality and compatibility limitations

Conversion cannot add information that is absent from the LDT file. An LDT generally describes one luminaire’s photometric characteristics; it is not a complete room calculation, installation drawing, or manufacturer datasheet.

Validate the PDF after conversion, especially the unit labels, decimal values, angular measurements, manufacturer metadata, and any special characters. Keep the original .ldt file with the PDF because lighting software can use the LDT for recalculation, whereas the PDF is normally presentation-only.