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DAY — the daylight scope

There is only one DAY code.

CodeSeverityWhat it says
DAY01errordaylight carries a value that is neither 0 nor 1

daylight is a binary declaration — whether the daylight test applies to this space — and it is the sole entrance to koyu light. Nothing is inferred from the type: write bedroom or write room, and without daylight:1 the space is not in scope.

So a wobble in the spelling of the value is a total loss of the verdict. Let daylight:yes through as a free attribute and the space drops silently out of scope, and light returns output indistinguishable from "every room passes". DAY01 exists for that one reason.

DAY01 — daylight is either 1 or 0​

error

grid X 0 3600 7200
grid Y 0 4000
level L1 0 h:2400 slab:150
space /L1/a room X1..X2 Y1..Y2 daylight:yes
daylight is either 1 (in scope for the daylight check) or 0 (out of scope): /L1/a carries daylight:yes

Cause — daylight carries something that is neither 1 nor 0. yes, true, on and 1.0 all fail.

Fix — write daylight:1 (test it) or daylight:0 (do not).

grid X 0 3600 7200
grid Y 0 4000
level L1 0 h:2400 slab:150
space /L1/a room X1..X2 Y1..Y2 daylight:1

Writing nothing is also a choice. With no daylight, the space is out of scope. DAY01 only looks at values that were written, so leaving it out never fires. Writing daylight:0 explicitly says "considered, and deliberately out of scope".

The type is irrelevant​

The daylight scope is declared, never inferred.

  • Write daylight:1 on a wet and the washroom is tested.
  • Write nothing on a bedroom and the bedroom is not.

This also hands the granularity to the writer. If a dwelling is written as one space, put daylight:1 on the dwelling; if it is split into rooms, put it on each room. Where you write daylight:1 is where you decide the denominator of the test.

What being in scope produces​

koyu light reports, per space, the ratio of effective window area to floor area.

grid X 0 3600 7200
grid Y 0 4000
level L1 0 h:2400 slab:150
space /L1/a room X1..X2 Y1..Y2 daylight:1
space /L1/b room X2..X3 Y1..Y2 daylight:1
space /out exterior
boundary /L1/a /out t:150
  window w:1800 h:1500 edge:S
boundary /L1/b /out t:150
  window w:400 h:400 edge:S
koyu light house.muro
✔ /L1/a	a	window 2.70 m2 / floor 14.40 m2 = 1/5.3 (needs 1/7 ≈ 2.06 m2)
✖ /L1/b	b	window 0.16 m2 / floor 14.40 m2 = 1/90.0 (needs 1/7 ≈ 2.06 m2)
✖ Short of 1/7: 1 of 2 rooms (this is a validation judgement)

The window area is the sum of w × h over the windows on that space's boundaries that carry an h:. A window with no h: cannot be counted — that the count is incomplete is reported by koyu validate as daylight.unknown. If the far side of a window is semi-outdoor and that semi-outdoor space has something above it (under a balcony, under an eave), a factor of 0.7 applies; if the sky is open above it, 1.0.

The verdict itself — whether 1/7 is met — is an architectural judgement, so it lives in koyu validate as daylight.ratio, not in check. check says only whether the declaration can be read.