[Erry91]

What this changes

M2: the calculation engine.

• Luminaires have a heading and a tilt. Tilt 90° is wall-mounted: the luminaire's nadir swings towards C0. IES tilt factors are applied, and a tilt outside the file's table is an error rather than a guess.

• Direct illuminance on any surface: horizontal, vertical (e.g. at fire-fighting equipment) or inclined.

• Grids:

  • over an area: a polygon, less a border;
  • along a route: the centre line, over its full width, with each corner counted once;
  • or points given one by one.

  Every grid is summed over all luminaires and capped at a million points.

• Statistics: min, mean, max, max/min and min/mean. One undefined point (e.g. at a luminaire's centre) makes them None, which a check will report as "cannot verify".

• Photometry plausibility warnings (gap 13), shown by luxpath photometry:

  • a relative file whose table emits more than its lamps;
  • an EULUMDAT file whose declared light output ratio disagrees with its table.

• Faster intensity lookup (binary search).

How you verified it

• cargo xtask ci, natively (macOS) and in the local Linux container, including the release-mode timing budget. Merged on the local checks (hosted CI unavailable).
• Exit criteria:
  • isotropic and Lambertian cases match their closed forms within 1e-6, point by point over a grid;
  • 100 luminaires × 10,000 points take 53 ms (budget 100 ms).
• Watched the tests fail: flipping the tilt direction and counting route corners twice each turn a test red.
• Hand-checkable numbers: every test states its arithmetic in a comment.

Life safety (AGENTS.md §2)

• No path reports "pass" when data is missing or ambiguous. Undefined points and tilts outside the file's table give no number.
• The engine still ignores walls between luminaire and point; this is recorded as an alpha blocker (gap 16) to be fixed before M4's checks.

Never panic (AGENTS.md §3)

• No new unwrap/indexing on input outside tests; non-finite inputs give None or errors; grid sizes are capped

Provenance (AGENTS.md §1)

• No text or values from a standard. Grid spacings and borders stay parameters for M4 to set from the text.
• Nothing from closed tools; no GPL/AGPL code

Records

• parity/features.toml: calc.direct-point, grids, tilt and vertical illuminance shipped
• docs/status.md, docs/gaps.md (rows 3, 8, 9 and 13 closed; 16 added), docs/roadmap.md, ROADMAP.md log