Set the moment
Press 0 for the sun — or open the Light door — and pick a place, a date, an hour.
Builder feature · free · in your browser
Study the Real Sun Over Your Plot —Solar Design Online
The sun in Builder is not a lamp on a stick. Positions come from the Meeus low-precision series to about a hundredth of a degree: choose a place, a date and an hour, and the shadows are the ones your building would really cast on the plot. Sun colour follows elevation — white at noon, gold at 12°, orange on the horizon — and the hemisphere light and fog follow the same curve. Play the day in 15, 45 or 120 seconds; let the night come, and 1,400 stars fade in through civil twilight with the moon lit by its true phase.
How it works — in the app
Play the day
Press Space: the whole day runs in 15, 45 or 120 seconds.
Sweep the year
Open the sun-path study and check the equinox and solstice arcs.
Walk the hour that worries you
Click the compass to face north, then step through the plot at that hour.
What you get
Study the real sun is one of fifteen feature pages covering what ships in Builder today — every claim here maps to a shipped, verified feature. The list below is the concrete surface:
- Real solar and lunar positions — Meeus low-precision series, about 0.01° on the sun
- Sun colour keyed to elevation: white noon, gold at 12°, orange on the horizon; hemisphere light and fog follow
- Day playback in 15, 45 or 120 seconds
- Real night: moonlight scaled by the lit fraction of the disc, 1,400 stars through civil twilight, a moon-phase billboard
- Exactly one shadow-casting light at a time — what you see is what lights the scene
- Compass with sun and moon pips, and a sun-path study over the year
FAQ
How accurate is the sun, really?
The Meeus low-precision series holds about 0.01° on the solar position, and QA checks the physics: solstice noon against the earth's tilt, equinox sunrise due east, equation-of-time extremes, polar day and night, and midsummer in Warsaw running 04:14 to 21:01.
Can I check the winter light on a north-facing room?
Yes — that is what a real ephemeris is for. Set the date to December, pick the hour you care about, and the shadows and interior daylight are the ones the building would really get, cast by a 4,096² shadow map fitted to the site.
What happens at night?
The sun hands over to the moon: light scaled by the lit fraction of the disc, its phase shown on a billboard, and 1,400 stars fading in through civil twilight. Exactly one shadow-casting light is on at a time, so the night stays as honest as the day.
More Builder features
Keep reading the tour, or jump back to the Explore hub for all fifteen.
Walk through itStep inside your 3D house design: WASD to walk, Shift to run, E opens the door in front of you, V for third…Open the feature →
Cinematic rendersRender your house through an 11-pass cinematic stack — GTAO, god rays, hexagonal depth-of-field, ACES grade…Open the feature →
Sculpt the terrainRaise and lower a BVH heightmap around your house, paint surface types with splats, and ring the plot with a…Open the feature →
Open the designer, set your plot's date and hour — the shadows will not lie.
No install, no plugin — a house builds itself the moment the page opens.