IFC Coordinate Checker
Find out whether a model knows where in the world it is, and whether its coordinates are far enough from the origin to cause trouble downstream.
Drop your IFC here
or
Large models work best on a desktop browser. Files above roughly 500.0 MB may exceed browser memory.
How it works
- 1Select an IFC file. It is read from your disk by your browser and goes no further.
- 2Site coordinates, placements, true north, map conversion and the coordinate reference system are read straight from the file.
- 3Each of the four georeferencing levels is reported as present or not, with the reason.
- 4Placements far from the origin are flagged, with what that costs in precision.
- 5Export the findings as CSV or JSON.
About IFC Coordinate Checker
Georeferencing is set once, at the start of a project, by one person, and after that nobody looks at it again until two models refuse to line up. By then the models have been issued a dozen times and every alignment anyone did by hand has to be redone.
The awkward part is that a model with no georeferencing looks completely normal. It opens, it has geometry, it has a site and a building. Nothing in it announces that it does not know where it is.
This tool reads what the file states: the site's latitude and longitude, the placement offsets on the site, building and storeys, the true north direction, and the map conversion with the coordinate reference system it targets. It then reports which of the four commonly used georeferencing levels the file satisfies and, more usefully, why each one is or is not present.
Distance from the origin is the second thing worth checking. A model whose geometry sits at survey coordinates is often hundreds of kilometres from its own origin, and past roughly ten kilometres single-precision floating point stops resolving millimetres. That is why geometry shimmers or z-fights in some viewers and not others. The fix is not to move the model but to keep the geometry near the origin and record the real-world position in the map conversion, which is what the highest level is for.
Everything here is read raw from the file. Nothing is normalised or corrected, so what the report shows is what the model actually contains.
Questions
- What are the levels this reports?
- They are the georeferencing levels the openBIM community uses in practice, usually written LoGeoRef 20 to 50: site latitude and longitude, a site placement offset, a project coordinate system with true north, and a full map conversion to a named coordinate reference system. They are a widely followed convention rather than a clause of the IFC standard, and the tool says so on the page. What it reports is which of them the file satisfies, which is a statement about the file's contents, not a conformance certificate.
- Why does it matter whether a model is georeferenced?
- Because federation depends on it. Two models that both know where they are line up on their own. Two models that do not have to be aligned by hand, and the alignment has to be redone every time either one is reissued. It also matters for anything that leaves the building: site surveys, existing topography, GIS, utilities, setting out.
- What is the difference between a site placement and a map conversion?
- A site placement moves the model's own coordinates. A map conversion leaves the geometry where it is and records the transformation to real-world coordinates separately. The second is much better behaved, because it keeps the geometry near the origin where floating point precision is good, while still saying exactly where the building sits.
- Why does distance from the origin cause problems?
- Most viewers and anything derived from a game engine keep vertex data in single-precision floating point. At around ten kilometres from the origin that format can no longer resolve a millimetre, so geometry starts to shimmer, snap or z-fight. The threshold is a rule of thumb rather than a specification, and whether it bites depends on the receiving application, which is why this is reported as something to look at rather than as a failure.
- Can it move the model or add georeferencing?
- No. Writing coordinates into a model changes where every element in it is, and doing that in a browser without knowing what else references those coordinates would be reckless. Georeferencing belongs in the authoring tool, set once at the start of a project. This tool tells you what is there.
- Is my IFC file uploaded anywhere?
- No. The file is read by your own browser using a WebAssembly IFC parser. The model is never sent to FreeBIMTools or anywhere else, and there is no upload endpoint for it.
- Can it read a Revit .rvt file?
- No, and no browser tool honestly can. RVT is a proprietary format that needs Revit itself. Export an IFC from Revit and this tool will read it.
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