UDI Categories - UDI failed?

Hi @mikkel,

Hope you’re doing well!

I’m curious to get your thoughts on the UDI categories, atm LBT is using a UDI, UDI_low, UDI_high.

Is there any reason UDI_failed is not also included?
Would you be interested in adding a UDI_failed category?
Do you know if there’s an “official” definition of UDI anywhere - I’ve looked at some of the papers where John Mardaljevic proposes and defines the metric, and from what I’ve read most of the academic papers on the subject include the UDI_failed category. Equally I’m sure I might’ve missed something!


Image from Climate Studio for reference: Custom Daylight Availability — ClimateStudio latest documentation


It’s a good topic. I would like to keep this thread alive and input my thoughts.

I agree that UDI in some cases is a more valuable metric.

I noticed that UK is using UDI as a metric and set UDI-a 80% as a threshold. (EFA daylight design guide - GOV.UK)
However, the US benchmarking is so customed with sDA + ASE combo. IES LM-83-12, an American national standard on daylight, is widely accepted in LEED and WELL. And this standard only talked about sDA and ASE, not UDI. – maybe that’s why LBT didn’t detail UDI, plus technically it is possible to customize the script to get the UDI_f result.


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