Hi HN — author here. iesna.eu is a browser-based ecosystem for working with photometric data: parsing standard luminaire files (LDT/EULUMDAT, IES LM-63, Oxytech, ATLA-S001), running design calculations against EN 13201 / ANSI/IES RP-8 / CJJ 45 / IES-IDA MLO, and (the part I most want to show off here) rendering real urban scenes in Bevy with the photometric data driving actual streetlight behavior, including sky-glow contribution.
The Skyglow Analysis demo loads a real LDT file into a Bevy scene (Khronos Bistro test asset).
The luminaire's intensity distribution drives the streetlight rendering directly — no fudging — and the sky-glow grade updates live as you adjust the uplight percentage. Swap to a full-cutoff fixture and the sky goes from F (Severe) back to A (Excellent). You can see the difference on the buildings as well as in the sky.
Stack: Rust core (eulumdat-rs and friends, ~20 crates handling photometric formats), Bevy for the 3D rendering, WASM for browser deployment. No backend; everything runs client-side. About a thousand lines of new code on top of the existing photometric library to make the Bevy integration work.
Things I'd love feedback on:
The atmospheric scattering model is currently single-scattering Rayleigh+Mie. Is that defensible for the use case, or should I move toward multi-scattering?
The Bistro test scene works well visually but isn't a controlled environment.
Anyone know of a public urban geometry asset that's more typical of real road-lighting evaluation?
The CJJ 45 implementation (China's national road lighting standard) is the only one I've had to reverse-engineer from translated PDFs.
If anyone has primary-source experience with it, I'd value a sanity check.
Open-source on GitHub (eulumdat-rs and the related crates).
Crates.io: eulumdat
