IES Files for Track Lighting: What They Are and How to Use Them in DIALux and Relux

Direct answer

An IES file is a plain-text photometric description of one luminaire: how much light it emits, in which directions, and how that distribution changes with angle. You load it into lighting design software — DIALux or Relux in most commercial projects — so the software can calculate illuminance on the surfaces you care about instead of guessing from a wattage.

Two things decide whether the result means anything. The file has to belong to the exact model, optic and colour temperature you are specifying, and its provenance has to be understood: a distribution generated by an optical design tool is a design prediction, while a distribution measured in a photometric laboratory is a test result. They are not interchangeable, and a calculation built on one should not be presented as the other.

HAOTAI publishes IES files for all sixteen TL01–TL05 LED track light models at /downloads/. They are preliminary optical design models. They are not LM-79 measurements and not a photometric test report, and each file says so in its own header. Measured photometric reports are requested per model.

What an IES file actually contains

An IES file (properly, an IES LM-63 photometric data file) is a text file with a small header and then a grid of intensity values. Read the header before you read anything else, because it tells you whether the file is the right file:

Header field	What it tells you	Why it matters
[TEST] / [TESTLAB]	Who produced the data, and how	Distinguishes a laboratory measurement from a design prediction
[MANUFAC]	The manufacturer the data belongs to	Confirms the file is not a third-party approximation
[LUMCAT]	The catalogue model	Has to match the model you are specifying, not the family
[LUMINAIRE]	The full luminaire description	Should name the optic and the body
[LAMP]	The light source or module	A changed module changes the distribution
[OTHER]	Free-text notes	Where a disclaimer such as “preliminary optical design model” belongs
TILT=	Whether the distribution is tilt-adjusted	TILT=NONE is what you want for a fixed luminaire
Number of lamps, lumens per lamp	The absolute output the grid is scaled to	A different lumen value rescales every result
Candela multiplier, vertical and horizontal angles	The resolution of the distribution	Coarse angular steps can smooth away a narrow beam
<n> below the angle list	Whether the file is absolute photometry	Affects how the software treats the data

The grid that follows has no geometry attached to it. It is a list of intensities against vertical and horizontal angles, and it describes light leaving the luminaire — not light arriving on a shelf. Where that light lands is the software’s job, and it depends on mounting height, tilt, spacing, room surfaces and the reflections the software is configured to model.

IES, EULUMDAT and LM-79 are three different things

These three terms get used interchangeably in supplier conversations and they mean separate things. Keeping them apart prevents most of the misunderstandings in a lighting package.

Term	What it is	What it is not
IES (LM-63)	A file format for photometric distribution data, used widely in DIALux, Relux, AGi32 and most design tools	A quality mark. A file can be in IES format and still be a rough estimate
EULUMDAT (.ldt)	A different file format for the same kind of data, common in continental Europe	A different class of accuracy. Either format can carry either kind of data
LM-79	A test method: how a luminaire’s electrical and photometric performance is measured in a laboratory	A file format, or a distribution curve

So “do you have IES files?” and “do you have LM-79 reports?” are two different questions, and a supplier answering yes to the first has not answered the second. A file can be perfectly usable for layout work and still not be a measurement. The honest answer describes which one it is.

There is a fourth term worth separating as well: EN 13032, the European family of standards covering how photometric data is measured and presented. Where a European project asks for measured photometry, EN 13032 and LM-79 are the reference points, and a preliminary design model satisfies neither.

Where our published IES files come from, and what they are not

The files at /downloads/ cover the sixteen TL01–TL05 models, at 3000 K and CRI 90, in IES LM-63-2002 format. Thirty-seven .ies files are published in total, alongside thirty-two spec sheets, covering the fixed 24° / 36° optics and the zoom ranges.

They are produced from the optical design of each model — the reflector or lens geometry, the LED module, and the modelled output — and then exported to the IES format. That makes them genuinely useful for early layout work, for comparing one beam option against another, and for checking whether a 24° or a 36° optic is the right starting point for a room. It does not make them measurements of a built luminaire.

Three consequences follow, and they are worth stating plainly because a tender document will ask about them:

• No individual unit was measured. The data describes the design intent, not the output of a specific production unit, and it therefore carries no production tolerance band.
• No laboratory was involved. There is no test report number, no accredited laboratory and no measurement date, because no measurement took place.
• The figures on the product pages and the figures in the file are the design figures. The system output values published for TL01–TL05 are the design values for the single-colour configuration. Where a dual-colour build is specified, output is approximately 70% of the single-colour figure for the same model, and the two must not be mixed in one calculation.

If a project requires measured photometry — because the specification names LM-79 or EN 13032, because a lighting designer has to sign the calculation off, or because the client is carrying an energy-compliance model — ask for it per model and state the model numbers. A measured report is not published for any model yet, so the request has to be raised with the project rather than assumed from the website.

How to load a track light into DIALux

The workflow is short, and most of the mistakes happen in the last two steps rather than the first two.

1. Get the right file. Identify the exact catalogue model first — TL01A50 and TL01A90 are different luminaires with different bodies and different outputs, even though they share a series. Then pick the file matching the optic you are specifying.
2. Import it. In DIALux evo, use the luminaire catalogue’s own-file import and point it at the .ies file. The luminaire appears as a user-defined luminaire, not as a catalogue entry, which matters: nothing will update it for you later.
3. Check the import. After import, open the luminaire’s properties and confirm the lumen value, the beam angle and the distribution shape are what you expected. An import that silently picks up the wrong lamp lumen count is the single most common way a calculation goes wrong while looking perfectly normal.
4. Place and aim it the way it will actually be installed. On a track ceiling, the mounting height is the rail height, not the ceiling void height. Tilt and rotation change the result far more than most people expect for a narrow optic.
5. Set the room surfaces, then read the results. Reflectances drive indirect illuminance, and a room configured with default surfaces is a different calculation from the room you are building.

Two practical points about track specifically. First, a track layout is usually an accent layout: the useful output is vertical illuminance on a display face, not horizontal illuminance on the floor, and a floor-plane average will not tell you whether the scheme works. Second, spacing matters more than quantity — a common failure is a rail with enough total output placed at the wrong pitch, which produces pools of light and dark bands along a merchandise run.

How to load a track light into Relux

Relux follows the same logic with different vocabulary.

1. Import the luminaire. Relux accepts IES files through its luminaire import; the result is a user luminaire in your own project database.
2. Confirm the data. Relux will show you the imported light distribution. Check the beam angle and the lumen output before you place anything, for the same reason as above.
3. Choose the right calculation. For accent and retail work the useful output is usually vertical illuminance on a defined surface. Set the calculation surface deliberately instead of accepting a working-plane default.
4. Model the rail, not just the luminaires. If the object of the exercise is to check whether a 3-circuit rail can carry the scheme, the rail is part of the model: it determines how many luminaires can sit on the run and how feeds are spaced.

If a project requires EULUMDAT rather than IES, note that .ldt files are not currently published. That is a request to raise per model rather than a file to download.

What to check before you trust a lighting calculation

A calculation is only as good as its weakest input. In track lighting projects the same five issues recur.

• Is the file the right variant? Optic, colour temperature and single- versus dual-colour configuration all change the data.
• Is the luminaire aimed as specified? A 24° optic aimed 15° off target shifts the whole pool of light.
• Is the surface the right one? Accent schemes are judged on vertical surfaces; a floor average answers a different question.
• Are the reflectances realistic? Dark exposed ceilings — common in retail fit-outs — absorb light that a default white ceiling would have returned.
• Is the result being presented as measured performance? A design model supports layout decisions. It does not support a compliance claim, and it should not be labelled as measured photometry in a report.

The last point is a documentation question rather than a technical one, but it is the one that causes trouble later. Label the data source in the calculation, so that anyone reading it six months afterwards knows what it was built on.

Using IES files in a tender or specification package

When a specification package goes out, the photometric data usually travels with it. A few habits make that package defensible.

• Name the exact model in the file list. Not “TL01 IES files” but the model code, the optic and the colour temperature for each file, so a reviewer can match file to specification without guessing.
• State the data source in the document, not only in the file header. One line — preliminary optical design model, not an LM-79 measurement — prevents the package from being read as a claim it cannot support.
• Keep the design figures and the delivered-unit question separate. A design model is the right input for layout. Production consistency is addressed through the drawing, the sample and the agreed inspection arrangement, not through the IES file.
• Ask for measured data early if you need it. Where the project’s compliance route requires measured photometry, raising it during specification is far cheaper than raising it after the order is placed.

What to request when IES is not enough

For some projects the IES file is the beginning of the question rather than the answer. These are the documents worth asking for, with the model numbers quoted in the request:

• Spec sheets for each model, giving power, output, body dimensions, beam options and mounting — these are already published at /downloads/ for the TL01–TL05 range.
• Measured LM-79 or EN 13032 reports for the specific models in the project, where the specification calls for measured photometry. Provide the model list and the standard the project references.
• EULUMDAT (.ldt) files, for design studios working in that format.
• Drawings for the individual models and for the track profile, so mounting and conductor arrangement can be checked against the ceiling design.
• Certificates covering the models, including the certificate numbers and the model ranges they name. Our /certificates/ page carries the watermarked previews and a downloadable index; full documents are supplied on request.

Document requests go to manager@fshaotai.cn. State the exact model numbers and the document type needed — that single sentence is usually the difference between a same-day answer and a week of clarification.

Frequently asked questions

Are your IES files measured or calculated?

They are calculated. The published files are preliminary optical design models derived from the optical design of each model, exported to IES LM-63-2002 format at 3000 K and CRI 90. They are not LM-79 measurements and not a photometric test report, and each file states this in its header. They are suitable for layout and beam-comparison work; they are not evidence of measured luminaire performance.

Why publish design models instead of waiting for measurements?

Because a designer working on an early-stage layout needs a realistic distribution before a project is won, and waiting for laboratory measurement of every optic variant would leave the whole range without data. Publishing the design model with its provenance stated is more useful than publishing nothing, and more honest than publishing it without saying what it is. Measured reports follow the specific models a project asks for.

Can I use these files for an energy-compliance calculation?

Not on their own. Energy and compliance routes generally require measured photometry referenced to a recognised test method, and a design model does not satisfy that. If your project’s compliance model needs measured data, tell us the model numbers and the standard the project references, and request measured reports for those models rather than using the published design files.

Which file should I use for a zoomable track light?

Use the file for the zoom setting you are specifying. TL04 uses a 20°–55° zoom range and TL05 uses 15°–55°, and the distribution at the narrow end is not the distribution at the wide end. If the design depends on the beam being adjustable in service rather than set once, model the narrow and wide ends as two calculations and check that both work.

Do you supply EULUMDAT files?

Not as published downloads. IES files are what the downloads page carries, and .ldt files are requested per model. If your studio works in EULUMDAT, say so in the request along with the model numbers.

What else do I need besides the IES file?

The rail system, the adapter and the luminaire are one assembly on a track ceiling, so the photometric file answers only part of the question. Confirm the track platform and the adapter for the models you are specifying, check the model-level certificate coverage, and confirm the current drawing before ordering. The buyer FAQ covers the commercial side, and the lighting track rails page sets out the rail platforms the TL range is specified with.

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Technical requirements differ by market and installation. Confirm final drawings, electrical configuration, samples and applicable standards before purchase.

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