Free online LDT to PNG converter

What the LDT format is

LDT is the common extension for EULUMDAT files, plain-text photometric files used to describe luminaires. The data can include luminous intensity distributions, lamp information, dimensions, symmetry, electrical values, and technical metadata.

Lighting manufacturers commonly create LDT files for distribution with their product catalogs. You may encounter them in DIALux evo, ReluxDesktop, lighting calculation software, luminaire configuration tools, and manufacturer photometric databases. An LDT file is not normally an image, so changing its extension to .png does not create a usable picture.

What the PNG format is

PNG is a raster image format suited to diagrams, screenshots, rendered lighting views, and web graphics. It uses lossless compression and supports transparency, so it preserves sharp labels and line work better than JPEG in many technical illustrations.

PNG stores pixels, not photometric measurements. A converted image can show a polar distribution, false-color map, floor-plan result, or luminaire preview, but it cannot retain the complete calculation data contained in the LDT file.

How to convert LDT to PNG

Using 101convert.com

1. Open the LDT-to-PNG converter on 101convert.com.
2. Select fixture.ldt or use the upload control to choose the LDT file.
3. Start the conversion and wait for the file to be processed.
4. Download the resulting .png file and check that the required lighting view and labels are visible.

This method requires no installed software. If the service cannot produce a meaningful image from a particular LDT file, use lighting software to render the data first; an LDT contains measurements rather than a predefined bitmap.

Using DIALux evo

1. Install and open DIALux evo, then create a project.
2. Import the luminaire through the luminaire or product-selection tools and select fixture.ldt.
3. Place the luminaire in a room or calculation scene so the software can display its photometric distribution or lighting result.
4. Run the required calculation, select the 2D, 3D, false-color, or polar view, and use Export or the relevant image-export command.
5. Choose PNG when the export dialog offers an image format, then set the output resolution and transparency options if available.

ReluxDesktop provides a similar workflow: import the LDT as a luminaire, create or open a scene, calculate the result, select the desired view, and export that view as an image.

Quality, compatibility, and limitations

• The conversion is a rendering. There is no single universal PNG representation of an LDT; the output depends on whether you render a luminaire preview, intensity curve, photometric web, or calculated room.
• Use a higher export resolution for printed reports. Increasing PNG dimensions after export does not restore detail lost during low-resolution rendering.
• Keep the original LDT with the PNG when technical traceability matters. The PNG does not preserve candela values, beam angles, luminous flux, or the original coordinate data.
• PNG is suitable for static sharing, but it cannot be loaded into lighting calculation software as a replacement for the LDT.
• If the LDT contains invalid syntax, incomplete photometric data, or unsupported manufacturer extensions, an importer may reject it or display an incomplete distribution. Opening the file in a plain-text editor can confirm that it is an EULUMDAT data file, but editing values can make the photometric file inaccurate.