Sun Studies

Daylight / shadow visualisation and analysis for AECO scenes.

• SunPosition.computeSunPosition — pure-math NOAA Solar Position Algorithm: (date, lat, lon) → { altitude, azimuth }.
• SunStudy — owns the geo-location + time cursor + a DirLight representing the sun; auto-aims, auto-tints, and auto-dims the light as the cursor moves.
• AnnualSunPlayer — scrubs the cursor through a single day or a whole year on a configurable wall-clock pace.

Usage

import * as xeokit from "@xeokit/sdk";

const study = new xeokit.presentations.sunStudy.SunStudy({
  view,
  latitude:   49.28,
  longitude: -123.12,         // Vancouver
  northAngleDegrees: 0,
  currentDate: "2026-06-21T12:00:00Z",   // summer solstice noon UTC
});

const player = new xeokit.presentations.sunStudy.AnnualSunPlayer({
  sunStudy: study,
  mode: "day",
  durationSeconds: 10,
  autoPlay: true,
});

study.onChanged.subscribe((s, pos) => {
  readoutEl.textContent =
    `alt ${pos.altitude.toFixed(1)}° / az ${pos.azimuth.toFixed(1)}°`;
});
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