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User Manual

Basic procedure

The basic operation of the online luminaire photometric data converter is very simple:

  1. Get an up-to-date web browser. Please refer to our compatibility information if anything doesn't work as expected.

  2. Drag a luminaire data file (Eulumdat, IESNA, CIBSE) to the file receiver at the top of the page, or pick one with the file selector.

    • With CIBSE format files, enter or confirm the total luminous flux in the pop-up dialog.

  3. The file will be sent to the server, returning a list of properties, a curve diagram, and a 3D-view of the distribution.

  4. Study the returned information until you are satisfied that this file really is the one you want to convert.

  5. If the file contains several variations (eg. several possible lamp types in Eulumdat), select one near the top.

  6. Select a target file type.

  7. Click "Download...".

Input File Formats

  • IESNA North american standard

    • Distribution type A (supported)
    • Distribution type B (not supported)
    • Distribution type C (Supported)
  • Eulumdat European standard (supported)

  • CIBSE TM14 UK standard

    • Distribution type 1 (supported)
    • Distribution type 2 (not supported)

There may be different formats in use in other parts of the world. If anyone can provide me with a formal specification and a number of example files (the more the better), I may consider supporting any format that has a non-trivial user base.

Output File Formats

  • Radiance Scene File For the Radiance Lighting Simulation System.
    This file can be included directly into a Radiance scene via oconv, as long as it is able to find the matching data file. If the latter is not in the same directory or on RAYPATH, then you may need edit the file and add the actual path to the brightdata primitive.
    The most convenient way to use those files is with the help of replmarks(1).

  • Radiance Data File The data file for Radiance. It is best to place it in the same directory as the matching scene file, or on the RAYPATH.

  • Text Data Table A plain text file tabulating the output values. You can print this file with a monospaced font for documentation.

  • Comma Seperated Values (CSV) For import into spreadsheets and other data mangling software.

  • Tab Seperated Values (TSV) For import into spreadsheets and other data mangling software.


  • This converter is not designed for mass conversions. If you plan to convert large numbers of files (even for formats not listed above), please talk to me. There will be a better solution.

  • Currently only files with distribution data arranged around a vertical axis of rotation are supported. This excludes IESNA distribution type B and CIBSE distribution type 2.

  • Some manufacturers, even large and prestiguous ones, may occasionally give you data files that violate the standards. Most often, but not always, this happens when they have converted their own original files into a different format. The online converter tries to identify the most common such errors, and if possible works around them. But in those cases where there is no unambiguous solution, it will reject the file with a diagnostic message.

  • The file size accepted for upload is currently limited.

Implementation details

The various luminaire formats are defined by different standard bodies in largely similar, but still sufficiently different ways to possibly cause confusion when they are used next to each other.

Orientation of the C-Plane
For circular or square shaped luminaires, the original C-0 plane can be used without further problems. For longitudinal luminaires, it gets more complicated. The Eulumdat format specifies that the C-0 plane is parallel to the short axis of the luminaire, while the IESNA format has it along the long axis. The converter will always rotate the luminaire definition and its distribution, so that the C-0 plane is parallel to the long axis. This is consistent with the fact that it will also be parallel with the longer edge of each marker triangle in the scene file which the luminaire definition is going to replace (assuming you use replmarks for that). Of course, the angular relation between luminaire shape and distribution data is not changed, we just "rename" the C planes internally.

Some manufacturers even disregard the standard, and create files in IESNA format where the luminaire is wider than long. This is done by most of those european manufacturers who offer files in both Eulumdat and IESNA formats, probably as a consequence of using broken conversion software. With a lighting calculation program that doesn't do any normalization, the result would be that a luminaire gets a different orientation in the scene, depending on which file format has been used. It seems that US manufacturers sometimes use the same trick, in order to get the "most interesting" curve into the C0 plane, mainly for asymmetric fixtures.

The converter will always look at the actual orientation of a luminaire, and normalize the internal definition in such a way that the length is really the longer axis, and the distribution data starts with the right values as the C-0 plane pointing the same way.

Privacy and Data Protection

File upload and storage

Since the actual conversion happens on the server, we must store your file there temporarily. It will be deleted again after a few days, typically within 48 hours after you have last accessed it. Files that fail to convert are deleted immediately.

Nobody else will ever see any of your files. In fact, most likely nobody even wants to see them. Since there is no reliable way to identify the source of any of the anonymously uploaded files, they have to be regarded as "data of unknown origin". There is nothing useful anyone could possibly do with such material. If you want me (and only me) to actually look at one, please see the "Support" section below.

Session Cookie

To keep track of which of the files temporarily stored on the server are yours, we deposit a cookie in your browser identifying your current session. This cookie will automatically expire 48 hours after your last upload. If your last cookie has expired, or if you deleted it manually before that, then the next upload will generate a fresh one, initiating a new session.


If you have any comments or questions, please talk to me. if you want me to look at a specific file (eg. because the converter doesn't do with it what you expected), then you should probably send it to me by e-mail, as I may not be able to get to the uploaded copy before the server automatically deletes it.

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