Free download of LDT, IES or even GLDF? Neste artigo, mostro-vos quais são as melhores plataformas para aceder a estes dados tão valiosos. Partilho também o meu sonho de uma plataforma que faz tudo, os problemas que encontro em algumas das que existem atualmente – e como seria a minha plataforma ideal.
Generally speaking, the most popular programmes also have a monopoly on the available LDT and IES files, as well as their own specific download formats, such as ULD and ROLF. If you’d like to know exactly what a lighting data file is, read this article first:
I will now outline the main platforms, along with their pros and cons – as I mentioned, the choice is rather limited.
The DIALux download platform. Here you can download a wide variety of luminaires in different file formats. The proprietary ULD format can be sent directly to DIALux with a single click. The LDT and IES files are a little harder to find – next to the technical details there is a tab called “Download”, where you can download a ZIP file. Luminaire manufacturers pay a considerable fee to be listed on DIALux LUMsearch.
Negative aspects:
- Language – DIALux is available in several languages, but the download platform does not support this. In the search field, often only very specific phrases work, with no variations accepted. As I am from Austria and we speak a German dialect, I often find it difficult to use the exact terms. There are many German manufacturers on this platform – but when searching in Portuguese, only three manufacturers appear. It all depends on how the manufacturer structures their descriptions – if If you use the right terms, it’s found; if you don’t, it disappears. The software clearly needs to be improved so that it can find the right products regardless of the language.
- Filters – there are filter options, but here too the manufacturers’ descriptions are often incomplete, meaning that many products do not appear in the results due to a lack of information. The result is that you cannot find what you are looking for.
- It is not yet possible to download GLDF files or search specifically for this format.
- It is not yet possible to... There are no similar products listed. I’ve found a light fitting I’m interested in, but I need it in a smaller size or with different specifications. There are no automatic suggestions for related products.
- Manufacturers don’t always keep their product ranges up to date. You might end up using a light fitting that has already been discontinued – it’s happened to me before.
Positive aspects:
- The platform can be used without registering – a major advantage!
- Grande oferta de luminárias decorativas em ULD – com modelo 3D apresentável e curva de luz incluídos.
- Many manufacturers are represented on the platform.
- DIALux also offers good support and has an active community – which is useful when questions arise.
Overall, I use this platform regularly, as DIALux is my main software. The download platform could do with some improvement – it isn’t up to date and the new GLDF data format isn’t available yet.
The Relux download platform. As with LUMsearch, you can download luminaires here in various file formats. The proprietary format is ROLF – which can be imported directly into Relux. LDT and IES formats are also available. Manufacturers pay an annual fee to be listed on the platform.
Negative aspects:
- Registration is required – unlike LUMsearch.
- GLDF is not yet available as standard.
- As I work with DIALux, visually appealing files are of no use to me – ROLF files cannot be imported into DIALux.
- Fewer light fittings than on LUMsearch.
- Less languages are available than on LUMsearch – and even then, it only works to a limited extent. ReluxNet offers filter options by text, country, manufacturer and item number – with rather unsatisfactory results. I’m not quite sure what the country filter means – when filtering for Portugal, simply all manufacturers appear. Do they deliver to that country? It’s not clear. With only four languages and no search support in other languages – rather unsatisfactory.
Positive aspects:
- More comprehensive product data than on LUMsearch – not just luminaires, but also furniture files, 3D objects, complete product families and sensors.
- The products are grouped into categories - making it easier to find similar products from the same manufacturer.
- The filter options work - with the exception of text search—a little better than in LUMsearch.
- The layout is more intuitive and user-friendly.
Overall, it’s difficult to keep everything up to date here as well—and new data formats like GLDF aren’t available yet. Since I have more experience with LUMsearch than with ReluxNet, this is just an initial assessment. A major advantage: the 3D object is already included. With DIALux, you have to convert it first, since the standard version of DIALux only imports 3DS files as furniture.
A platform with a unique concept—here, the focus isn’t on lighting design, but rather on 3D rendering. The IES Library collects IES files provided by manufacturers on their own websites and brings them together in one place. The platform is still relatively new and offers three plans: Free (€0), Starter (€1/month), and PRO (€3/month).
Negative aspects:
- The filter and search functions are only available starting with the Starter plan (€1/month)—a major drawback, since without a subscription, it’s difficult to perform targeted searches.
- The free plan offers only minimal benefits compared to unregistered users.
- Very limited product information - only the lighting effect is shown, with no fixture visible.
- Less appealing to traditional lighting designers—the platform is clearly geared toward rendering software such as Blender, 3ds Max, or KeyShot.
- There is no direct link to the manufacturer's website - only the item number.
- The filter function doesn't really work well, even on the paid plan—the categories aren't very helpful. When I searched for "table" hoping to find a table lamp, the first result was an adjustable track light. In my opinion, you can save yourself the €1/month for the Starter plan.
Positive aspects:
- Over 550,000 files available – many manufacturers represented.
- IES files can also be used in DIALux and Relux, despite the focus on rendering.
- The platform fills a real need - designers sometimes require actual light sources to create realistic renderings. It is particularly useful for interior designers, as the products can be purchased and all relevant information is available for ordering comparable lighting fixtures.
Overall, it’s a different concept from LUMsearch or ReluxNet - more geared toward visualizers and architects who work with rendering software than toward traditional lighting designers. There’s also the question of whether the data is up to date - it would be necessary to check each item directly on the manufacturer’s website.
Direct download from the manufacturer
Another option is to download the files directly from the manufacturer’s website. Almost all major lighting manufacturers provide lighting data on their product pages—typically LDT, IES, and 3D models or technical data sheets, and occasionally ULD, ROLF, or GLDF files as well.
Negative aspects:
- You need to know in advance which manufacturer you are looking for - you cannot search across multiple manufacturers at the same time.
- Every website has a different structure - sometimes the files are easy to find, other times they’re well hidden.
- Registration is often required.
- It can be time-consuming when you need data from several different manufacturers.
- Too many unnecessary clicks - you have to repeat the entire process for each light fixture, and then start from scratch for the next one.
- It's hard to find products from other manufacturers that aren't already well-known.
Positive aspects:
- The most up-to-date data - maintained directly by the manufacturer.
- Typically, the most comprehensive datasets available.
- Often accompanied by additional documentation - DWG files, 3D models, and technical data sheets.
- You can contact the manufacturer directly for expert assistance.
- Many more versions available - by color temperature, wattage, etc.
For experienced lighting designers, this remains the preferred method. They have their go-to suppliers; they call to say what they need and receive the product or file directly. It might take a little longer—but the version will always be up to date, because there’s a relationship of trust and they know the person on the other end.
If you don't know of any manufacturers in the area yet, you can find a list here: Manufacturers
my dream website
My ideal platform would look like this: a simple, eye-catching layout—dark, luxurious, with large product images. Hover your mouse over a light fixture and it turns on. No cluttered interfaces, no hidden downloads.
The search would be powered by AI—I describe what I’m looking for in my own language, and I get matching results. No need to guess which keyword the manufacturer used. No need to search in Portuguese and suddenly see only three manufacturers.
Each light fixture would have all relevant file formats readily available—GLDF for quick download. No need to click through multiple tabs or search separately on the manufacturer’s website. Everything in one place, always up to date. When you click on a product, you can interact with an AI to find out which formats are available, what color temperatures are offered, and what wattages are available. And all the manufacturer needs to do is provide their technical data sheets.
Similar products would be displayed automatically—and not just from one manufacturer, but from many. After all, how often do we find the perfect light fixture, only to realize we need it in a different style?
