Where infrared.city fits
3,204,804 simulations run on Infrared Core (as of 29 Oct 2026).
infrared.city runs 12 models from one engine, Infrared Core, among them wind, wind comfort, sun, daylight, radiant heat and felt heat (UTCI). It works on real 3D building and terrain meshes, in a browser app, through an API and SDK, and in plugins for Grasshopper, QGIS and ArcGIS. Felt heat for 1 km² takes about 5 s once the geometry is uploaded, and 400 km² took 44 s as four 100 km² runs in parallel. Run times are not like for like across tools: area, grid, simulated hours and physics differ. Sun, sky and radiant heat come from ray tracing. Wind comes from an AI model trained on CFD results, not from a CFD run for each request.
- You need answers for many design options in seconds, not in hours to days of cluster time.
- You work in a browser, Grasshopper, QGIS or ArcGIS, or through an API, with no cluster to operate.
- You need wind comfort, sun, daylight and felt heat from one engine for the same model.
- You need an hourly city layer for a digital twin.
Use both
PALM-4U resolves turbulence and the atmosphere in a detail that infrared.city does not try to match. infrared.city gives a fast answer for each option.
Use infrared.city for the decision step. Use a detailed model such as PALM-4U for a city climate study or a final check of one chosen design.
Facts side by side
| infrared.city | PALM-4U | |
|---|---|---|
| Method | Ray tracing for sun, sky and radiant heat; wind from an AI model trained on CFD results (no CFD run per request) | Large-eddy simulation (optional RANS) on cells; building surface and indoor model; comfort indices PT, UTCI and PET |
| Run time | About 5 s for 1 km² of felt heat (UTCI, 08 to 18 h, geometry uploaded, measured); 400 km² in 44 s (four runs in parallel) | 39 h of compute for 8 wind directions of 6 simulated hours each, on 0.18 km² at 1 m, with 300 cores (handbook case, wind comfort) |
| Runs as | Cloud: browser app, API and SDK, plugins | Large compute clusters (HPC); small domains on workstations |
| Licence and pricing | Tokens: free start with 900 tokens, plans from €240 a year | Free, GPL v3 |
The run times are not like for like: PALM-4U resolves turbulence over time; the area, grid, simulated hours and analysis differ.
The infrared.city values repeat the full comparison. Each value for PALM-4U comes from the sources below.
Sources
- Maronga et al. (2020), Geosci. Model Dev. 13:1335 , accessed 24 Oct 2026.
- Krüger, Burmeister and Winkler (2023), PALM-4U Handbuch für die Praxis, ProPolis, p. 26 , accessed 24 Oct 2026.