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3D view unavailable

WebGL is not available here. The sun-path diagram below uses the same formulas as the 3D view.

London Landmarks Photo Quest

Sun, shadow, fog and rain light · 51.5°N · fps -

Mission

Level

Sun & time

Date-

Time (London clock)-

Time speed

Presets

Shadow of

Weather

Visibility V (Koschmieder)-

Camera (exposure triangle)

Aperture f/

Shutter

ISO

Auto exposure (aperture priority)

Focal length (35 mm equiv.)-

Rule-of-thirds grid

Photos

No photos yet. Press Space or the shutter button.

Graphs

Settings

Quality

Keys: [ ] date, , . time, T speed, 1-4 weather, P next spot, C camera, F/S/I then arrows = aperture/shutter/ISO, Space shutter, V shadow vector, Q quality, Ctrl+Z/Y undo/redo, ? help.

The science

Sun position

Declination δ = 23.44° sin(360°/365 · (N − 81)), equation of time EoT = 9.87 sin 2B − 7.53 cos B − 1.5 sin B (minutes, B = 360/365 (N−81)), hour angle H = 15° (t_solar − 12), then sin(alt) = sinφ sinδ + cosφ cosδ cos H with φ = 51.5°N. Clock time is converted with UK summer time (BST, 29 Mar to 25 Oct in 2026).

Shadow length

L = h / tan(alt), pointing at azimuth + 180°. A 96 m tower at 20° throws 263.8 m. Below about 5° the shadow is very long and the light is weak and red.

Exposure

EV₁₀₀ = log₂(N²/t) − log₂(S/100). A scene needs EV = log₂(E/2.5) for illuminance E (lux). Direct sun uses a Meinel-style air-mass law, 133 klx × 0.7^{AM^0.678} × sin(alt), plus sky light; weather multiplies the total (illustrative model values). f/8 1/125 ISO100, f/5.6 1/250 ISO100 and f/8 1/250 ISO200 give the same EV.

Wet road

Fresnel (Schlick): F = F₀ + (1 − F₀)(1 − cosθ)⁵, F₀ = 0.02 for water. At grazing angles (looking far along the street) F rises towards 1, so a wet road becomes a mirror. The reflection is a planar mirror render of the scene, not a full ray tracer.

Fog

Koschmieder: V = 3.912/β and T = e^−βd, the 2 % contrast threshold. The scene fog is exactly this exponential law.

Colour temperature

Typical values: about 2900 K at the horizon, 3000-4500 K in the golden hour, 5500-6500 K at midday, 9000 K+ in the blue hour sky. The sunlight tint follows a table of these values.

Simplifications

The sun model is accurate to about 1° (checks below); no refraction near the horizon, no Rayleigh/Mie sky scattering model; the sky and clouds are procedural; the moon is a fixed light at night; reflections are planar; the London kit is stylised, not survey-accurate; exposure is rendered as a brightness factor on tone mapping. Not an astronomical or weather tool. Never look at the real Sun through a camera.

Independent project, not affiliated with any institution, building owner, transport operator or weather service. The bus, phone box and lion are generic designs.

Live numerical checks

Build notes

Blender 5.2 assets: London kit (trimmed and decimated copy of the shared model, Draco GLB), new props (bus, phone box, lamp, balustrade, stone lion, planter, tripod) with Cycles-baked albedo, AO and roughness/metal maps, and a Cycles-baked wet-cobble PBR set. Three.js r160 + WebGL2. Slice v1: dynamic sun with shadow map, four missions, history-of-air text and blue-hour/golden-hour extras are planned for later.