Annual Daylight UDI, UDIlow, UDIhigh Should Sum to 100%? LBT 1.4.0

Hi LBT team @chris ,

I am trying out the newest LBT tools on a test box for a daylight analysis and noticed that the UDI, UDIlow, UDIhigh does not sum to 100%

Each is % of occupied hours within each range so I thought adding the three would sum to 100% but it’s summing up to 94%. Where is the other 6% of occupied hours?

I’ve tried adding in schedules but the same issue.
Have I missed something very obvious? Attached is the sample gh script and rhino with the box. (62.1 KB)
UDI_Issue.3dm (89.8 KB)

Any explanations would be appreciated! Thank you!

Can’t replicate your case, but i do get a combined value of 100 when i take each sensor separately.
Maybe taking the average not necessarily give 100.


Hi @AbrahamYezioro ,

Thanks for looking into it. See your averages sums to 99.99% which makes sense as it’s close to 100%. Not sure why mine is 94%. Doing it individually, also sums only to 94%.

I tried a different weather file (Milan), it sums to 97%. Then tried Doha weather file, it sums to 100%.

Very confused… could it be something with location? Which radiance version are you using?

My Radiance is 5.4a.
Which epw are you using?

Weird …

@AbrahamYezioro mine is also 5.4a.

Tested these four from the ladybug site - only doha behaved normally. Might it be a rounding error that somehow accumulates throughout the simulation year?

Tried the Milano epw and get 97.3.
Can’t explain. Maybe the epw is missing some data at some hours …?

Thanks @AbrahamYezioro for trying! Glad it’s not just me I guess. Will try to look into the weather files see if I find anything

Sorrow of many is a fool’s consolation (old spanish saying :slight_smile: )

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Maybe the default thresholds of this component have a little gaps.-t 300 -lt is 100.
I guess.