YAMAKEN SHADOW STUDY
Building Shadow Study and Sunlight Hours Calculator
Compare existing conditions with two design proposals, measure direct sunlight at a selected point, and prepare an explainable early design report.
Click the map or search for a place.
PLACE & CONTEXT
Site map
OPTIONAL CONTEXT
Nearby OSM buildings
Loads mapped building outlines only after you ask.Not loaded. Building availability and height detail depend on local OSM data.
Building data quality
OPTIONAL CONTEXT
Terrain shadow
Calculates an approximate shadow mask from global elevation tiles in this browser.Not calculated. Terrain is sampled on a grid and is approximate.
READ THE RESULT CAREFULLY
Calculation notes
Calculated from the selected coordinates, local date, and local time.
Only buildings mapped in OpenStreetMap are loaded. Missing outlines are not inferred.
Mapped height is used first, then floor count. A visible estimate is used when both are missing.
This is an early-stage visual estimate, not a survey, permit drawing, or legal compliance result.
Save, share and report
Keep the complete comparison in a reproducible link or prepare an English-language early design report.
FREE EARLY DESIGN TOOL
A building shadow study you can inspect and explain
Yamaken Shadow Study is a free browser-based tool for architects, urban designers, homeowners and project teams. It turns a place, date and simple building model into a readable plan-view shadow estimate. Its purpose is early comparison: understanding how a proposal may change sunlight around a site before detailed survey and compliance work begins.
Compare existing and proposed buildings
Keep an Existing baseline and develop Proposal A and Proposal B independently. Use the same map position, local date and time for every option, then switch between them without rebuilding the model. A proposal can contain multiple buildings, connected 3D parts or trees.
Estimate sunlight hours at a point
Pick a ground point on the map and calculate direct sunlight across the selected day. Results show approximate sun duration, gained or lost sunlight against Existing, first and last direct sun, blocked intervals, and all three scenarios on one 10-minute timeline. The result also names the main modelled object behind a material change when the calculation supports it.
See the assumptions behind the result
Mapped building height is used when available. Floor count is converted using a visible three-metre assumption, and an explicit estimate is shown when neither value exists. Missing building outlines are not invented. The interface and report keep these data-quality limits visible.
How to prepare an early shadow comparison
- Find the site.Search for a city, address or landmark, or use the map to place the planned object.
- Add context.Load nearby OSM building outlines and, where relevant, calculate the optional terrain shadow.
- Build the options.Edit Existing, Proposal A and Proposal B with simple dimensions or the multi-part 3D editor.
- Measure and report.Pick an analysis point, compare daily sunlight, copy the reproducible link and create the Shadow Study Report.
Useful during early planning
The tool can support conversations about gardens, courtyards, neighbouring open space, building massing and alternative layouts. The shared link lets another person reopen the same location, date, analysis point and three proposal states.
Designed for clear reports
The English Shadow Study Report records the selected scenario, object dimensions, approximate sunlight periods, source quality and calculation limits. It prints as an A4 PDF that can accompany an early design discussion.
Professional limits remain important
The result is an early-stage visual estimate on level ground. It does not replace a measured site survey, verified 3D city model, planning authority method, rights-to-light assessment, permit drawing or legal compliance review.
Building shadow study FAQ
What is a building shadow study?
It examines where shadows from existing or proposed buildings may fall at selected dates and times. This tool adds a daily point analysis so you can also compare approximate direct sunlight duration.
Can I compare two design proposals?
Yes. Existing, Proposal A and Proposal B store separate planned-object sets while sharing the same site, date and analysis point.
Does it include surrounding buildings?
Only when you press “Load nearby buildings.” The tool uses available OpenStreetMap outlines and labels whether each applied height was mapped, derived from floors or estimated.
Does the sunlight calculation include terrain?
The daily point comparison currently includes loaded OSM buildings and planned objects. The optional terrain layer is a separate approximate visual calculation and is identified as excluded from the point total.
Can I use the report for a planning application?
It can help explain an early proposal, but it is not a certified planning or legal assessment. Confirm the authority’s required method, survey information, dates, times and presentation standards.
Is Yamaken Shadow Study free?
Yes. The web application can be used without a paid subscription. External map and data services remain subject to their availability and coverage.
Prefer Japanese? 日本語版の日影シミュレーター
REPORT PREVIEW
Shadow Study Report
DATA & PRIVACY
External services
Search terms are sent to Nominatim when you press Search. Coordinates are sent to Open-Meteo to resolve the local time zone. Map tile numbers are sent to OpenStreetMap. Coordinates and radius are sent to Overpass only when you load nearby buildings. Terrain tile numbers are sent to the Mapzen Terrarium archive only when you calculate terrain shadow. Short-lived browser caching reduces repeat requests.