GLDF - Global Lighting Data Format

Hello all,

I have just come across a new electronic file format for light fittings, called GLDF Global Lighting Data Format. GLDF is being developed by Relux and Dialux. It’s a royalty-free open format. The roadmap shows that the full specs will be release over the course of this year.

What is exciting about this new format is that the full luminaire geometry is included in OBJ format. In different levels of detail (LoD). How cool is that?

The web site already contains quite a bit of documentation, with more to come soon.

Hi Axel & all,

I had come across this, too. I have no further insight into this than what is published on the website, but this appears to be a rather ambitious approach bundling a 3D-description of luminaires (L3D) and an advanced photometric description (GLDF) of luminaires as well as sensors.

GLDF seams to go significantly beyond the known IES approach, e.g. with representions for spacial inhomogenity due to multiple light sources per luminaire, control, spectral power distributions and dimming.

L3D not only is based on OBJ, but also accounts for geometric constraints for the installation / aiming of luminaires. This may lead to some kind of parametric modelling of luminaires that would ensure that no impossible configurations are modelled.

There are github repositories for the varios components, so the entire development appears to be very transparent:

Since this is a joint effort by two developers of lighting simulation software (Dial and Relux) rather than the next closed and proprietary format, it might be worth to think how Radiance could provide an interface, too.

Best, Lars.

1 Like

Sounds great – definitely worth following! I remember decades ago, when the IES lighting committee was considering adding geometry and materials to light source descriptions, which was how MGF got started.

I wonder how they are defining materials to go with the OBJ geometry?

Really exciting! I will reach out to the buildingSMART group to see how they can integrate this with BIM data!

I guess one intention is to create a luminaire data format (and more) for BIM: “optional use of all ~350 CEN/TS 17623 - ZVEI BIM properties”.

GLDF has been presented at the congress “LICHT 2021”:
Lichtplanung: BIM und Lichtberechnungsprogramme (YouTube, talks in German)

Summary from DIAL: Uniform data format for the lighting industry: Global Lighting Data Format

Good find!

packing the various types of data into a zip file makes sense, as does
encoding the specifics as XML. If I had time, I might actually try to
support it with Online Converter for Luminaire Data Files-

Obvously, the folks from Dial and Relux created this solution so that
the luminaire manufacturers would not have to prepare two different
packages for each of their softwares anymore (or even more if they want
to support other programs).

While this is certainly a great step in the right direction, I’m still a
little bit disappointed, though… (can’t do right for some people, eh?)

It looks like they will just cram some IES/Eulumdat files in there,
are then attached via XML to certain surfaces. (In the
they say “we already have Eulumdat, so we don’t need to replace it”).
What I was really hoping for was an XML definition for the acutal
luminaire photometry.

Both IES and Elumndat show their age in a lot of ways. Both are not
stringently enough, which leaves too much wiggle room for the data
At the same time both impose unnecessary limitations on the data they
represent. And thirdly both are not really well structured, with a lot
the information subject to interpretation by humans, while the software
processing them is left guessing about what it really means.
And then there are CIBSE TM14 with even more limitations, an ISO
that has never caught on, and a few more niche formats.
If you’re familiar with the term “technical debt”, this is a perfect

Am I the only one who ever dreamt of a well thought out XML format for
the photometric data?
If that was supported by such a universal package format, then it might
actually get some traction.

Any takers? :wink:



I’ve heard of this work and was going to look into it, as part of an “expand ies2ad“ project, but I am currently out of most everything, as I am sitting in the hospital recovering from two broken wrists. To be continued…

I’m a general dubious of this Standard, as XML often creates a lot of excess verbiage and structure while adding little in utility. XML is not generally being used for new standards work. On the other hand there are existing XML libraries which we can easily incorporate into our work.

To be continued …

Well actually GLDF is not a replacement for ies and eulumdat, it does include those files as file include inside the zip container called .gldf.
What it can do so, is to override metadata like system_power and system_lum_flux.
Which makes it even more complicated, bcs you would need to recreate the light distribution file accordingly…

ANSI/IES TM-33-18 is an XML replacement for LM-63 and Eulumdat. So far it has not seen wide adoption.