The third lighting engine, different glare model, stronger outdoor handling, and when to choose it over DIALux on a Saudi project that needs both renderings and a tight UGR study.
Same data model as DIALux, parallel feature set, costs nothing. Adopted by Zumtobel, Glamox, ERCO catalogues. Most lighting designers run both in parallel.
Relux uses a slightly different UGR averaging weighting that several Saudi healthcare and education consultants prefer. Check the project spec before picking the engine.
Tilted poles, asymmetric distributions, rotated luminaires, Relux handles these without the import quirks DIALux sometimes shows on older IES files.
DIALux evo wins on photorealistic visualisation. Use Relux for the calc, DIALux for the picture if the client wants both the engineering and the magazine shot.
Unified Glare Rating limits by space, Relux's primary verification metric.
| Space | UGR_L max | Source |
|---|---|---|
| Drafting / CAD work | UGR ≤ 16 | EN 12464-1 T5.26 |
| General office | UGR ≤ 19 | EN 12464-1 T5.26 |
| Classroom | UGR ≤ 19 | EN 12464-1 T5.36 |
| Conference room | UGR ≤ 19 | EN 12464-1 T5.26 |
| Hospital ward | UGR ≤ 19 | EN 12464-1 T5.46 |
| Retail | UGR ≤ 22 | EN 12464-1 T5.33 |
| Circulation / corridor | UGR ≤ 25 | EN 12464-1 T5.1 |
Glare drives complaints more than illuminance ever does.
Relux UGR depends on observer position and line-of-sight. Run the UGR grid from each typical workstation and orientation. A single room UGR is meaningless, pick the worst-case view.
Office luminaires must hold ≤ 3,000 cd/m² above 65° from nadir. UGR 19 fails if any luminaire exceeds this at any viewing angle. Pick fixtures with steep beam cutoffs and louvre optics, not flat diffusers.
Relux integrates with climate-based daylight (CBDM). Window orientation, blind operation, and electric lighting need joint analysis. Saudi west-facing windows are glare bombs from 14:00 to sunset year-round.
Glossy desks, polished marble, glass partitions reflect light into eyes from oblique angles. Spec matte finishes for work surfaces and run a reflective-glare check separately from direct UGR.
6,500 K appears glarier than 3,000 K at the same luminance, the eye's photopic sensitivity peaks in green-yellow, while 6,500 K weights toward blue. For comfort-critical spaces, design at 3,500-4,000 K, not 5,000 K+.
Every office, classroom and clinical fitout we design ships with a Relux UGR compliance report at typical viewing positions. UGR ≤ 19 standard, lower on request.
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