Daylight & sunlight assessment — sun, shadow and overshadowing in 3D
Parcela simulates the sun moving over your plot and casts real shadows from your proposed massing and from neighbouring buildings, across the day and through the seasons. It is the kind of daylight and sunlight study an architect normally prepares, available automatically online.
See the sun study for your plot →How to check daylight, sunlight and overshadowing on a plot
- 1Pick the plot. Select your plot by postcode, address or on the map — Parcela loads its outline and the surrounding building context from spatial data.
- 2Set the massing. Define your proposed building, or use an A/B/C scenario; the app builds a 3D model on the plot’s real terrain.
- 3Read the shadows. View the sun path and shadows for any date and hour — assess sunlight to rooms, overshadowing of neighbours and the potential for rooftop solar PV.
Sun simulation on real 3D terrain
Parcela builds the plot on a digital terrain model and surrounds it with neighbouring building geometry. The sun follows its true path for the site’s latitude and date, so the shadows match what you would see on the ground — at the spring equinox, midsummer or the depths of winter.
From sunlight to solar PV
The same study indicates rooftop solar potential — how many hours of sun reach each roof plane across the year, accounting for overshadowing from the surroundings.
Frequently asked questions
What is the difference between daylight, sunlight and overshadowing?
Daylight is the diffuse skylight reaching a window; sunlight is the direct sun a point receives over the day; overshadowing is the shadow your massing casts onto neighbouring property and gardens. Parcela models all three in one 3D scene.
Does the study include neighbouring buildings?
Yes. The simulation casts shadows from both your proposed massing and existing surrounding buildings, using their geometry, so you can see overshadowing realistically.
Can I use this for a planning application or a right to light dispute?
Parcela is a fast, indicative design and due-diligence tool. A formal daylight and sunlight assessment to BRE Report 209, or a right to light report, must be prepared by a qualified consultant — but Parcela lets you spot a problem early, before you commission one.
Why check sunlight before buying a plot?
A tall building to the south can permanently overshadow a plot, make it hard to meet daylight and sunlight guidance for a new dwelling, and undermine the case for solar PV. It is far cheaper to check before you buy.