Can I do a shadow study from an IFC file without a render tool?

Yes. If the IFC is georeferenced, its location and true north are in the file. IFC Viewer Online reads them, places the sun for any date and site-local time, and casts shadows on the model in the browser — no export, no plugin.

Why is my shadow study pointing the wrong way?

Almost always true north. Many models are drawn with project north up and the rotation to true north is stored separately, or not at all. A study that ignores it rotates every shadow by the same error. Check where the tool got north from before trusting the result.

What if my IFC has no georeferencing?

A good tool says so instead of silently assuming a location. You can then set the location manually, by coordinates or by city — but treat the result as indicative until the model is georeferenced properly.

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Tools & comparisons · 2026-10-02 · 9 min

Sun and Shadow Study From an IFC Model, in the Browser

A shadow study usually means exporting to a render tool and guessing the north angle. A georeferenced IFC already knows where it is and which way is north — so the sun can be placed correctly at any date and time, in seconds, without leaving the browser.

Sun and Shadow Study From an IFC Model, in the Browser — IFC Viewer Online article cover

"Will the new block shade the playground in December?" is a question that arrives at every planning meeting, usually the day before. The traditional answer is an export to a rendering tool, an hour of setting up the sun, and a slightly nervous guess about which way north is.

A georeferenced IFC already contains the two facts that guess is about: where on Earth the building is, and how the model is rotated relative to true north. With both, the sun's position at any moment is a calculation, not a setting.

Key takeaways

A correct shadow study needs three inputs: latitude and longitude, true north, and the site's local time zone. A georeferenced IFC carries the first two.
The most common error is north. A study that uses project north instead of true north is wrong by the same angle at every hour.
A tool that silently falls back to a default location produces convincing, wrong shadows. Look for one that tells you where the location came from.

What the sun needs from your model

Diagram of project north versus true north rotated 28 degrees, with the inputs a correct sun and shadow study needs: latitude, longitude, true north and time zone — Project north is not true north. A sun study that ignores the rotation turns every shadow by the same angle.

Input	Where it comes from	If it is wrong
Latitude / longitude	IfcSite reference coordinates, or IfcMapConversion with a known CRS	Sun height is wrong — shadows too long or too short
True north	The rotation stored in the georeferencing	Every shadow is rotated by the error
Time zone	Derived from the location	The study is shifted by an hour or more
Date and time	You choose it	—

If you are not sure whether your model is georeferenced — or why it sits two kilometres from where it should — start with IFC coordinates and georeferencing. Everything below depends on it.

Where the location came from matters as much as the location

A sun study that looks right and is wrong is worse than none, because it gets put in a planning report. The single most useful thing a tool can do is say where it got its inputs from.

From the model: the georeferencing was found and used. This is the result you can defend.
Set by you: coordinates or a city were entered by hand. Fine for an early check; note it in anything you publish.
Default: nothing was found and the tool assumed a location. This should never be silent — ours shows a blocking notice rather than casting shadows for a city you are not in.

Running the study

Open the IFC It loads in your browser; the model is never uploaded.
Turn on the Sun & Moon study The location and north are read from the model, with a badge showing their source.
Pick the dates that matter The solstices and equinoxes are the usual set: 21 June for the longest day, 21 December for the lowest sun.
Scrub through the day Drag the time; sunrise and sunset are marked on the timeline so you never study a sun below the horizon.
Save presets per file "Winter, 10:00" and "Summer, 18:30" become one click on the next revision of the same model.

The moon is there too, with its phase — less important for planning, surprisingly useful for night renders and for explaining to a client why the courtyard is dark at 22:00 in winter.

Sharing a sun study without sending a model

A study is only useful if the people who decide can see it. The same moment can be opened by a link: the date and site-local time travel in the URL, and the time zone is resolved from the model's own location, so "21 June, 18:30" means 18:30 on site, not in the viewer's office.

?model=https://your-host/model.ifc&solar=06-21T18:30
?model=https://your-host/model.ifc&solar=12-21T10:00&moon=1

The form without a year always means the current year, so a link in a planning document stays valid. The full set of parameters, and how to put the study on a web page or a CDE panel, is in how to embed an IFC viewer.

Adding the neighbours

A building does not cast shadows in a vacuum, and neither does it receive them in one. Placing the model on a 3D map with the surrounding buildings and terrain turns "does our block shade the playground" into "do the existing towers already shade it". That workflow is covered in viewing an IFC on a 3D map.

Sun and Shadow Study From an IFC Model, in the Browser