IFC viewer

What an online IFC viewer does

An IFC viewer opens an Industry Foundation Classes (.ifc) building model and shows its 3D geometry together with the data attached to each element. This one runs entirely in your browser: choose a file and it is parsed on your own device by web-ifc, a WebAssembly IFC engine running in a background worker. Nothing is uploaded, and there is no account or software to install.

Once the model loads you can orbit and zoom the geometry, click a wall, door or slab to highlight it, isolate it from the rest of the model, and read its attributes, property sets and quantities in a panel beside the canvas. Section planes cut the model on any axis, a measure tool reports the distance between two clicked points, elements can be coloured by class or by storey with a legend, and up to five camera views can be saved and restored. A searchable table lists every entity that has a GlobalId, and the filtered list downloads as CSV.

It is built for the quick look: checking a consultant's export before a coordination meeting, confirming what a contractor sent, or opening a model on a machine without Revit, Archicad or a desktop viewer. It reads IFC2X3 and IFC4 files up to 50 MB. IFC4X3 (IFC 4.3) files are not supported.

How to use the IFC viewer

1. Click Choose an IFC2X3 or IFC4 file, pick a local .ifc file up to 50 MB, then press Open model. To try the workflow first, press Open IFC4 sample or the IFC2X3 sample link.
2. Watch the status line while the worker starts the parser, reads the records and builds geometry. When it finishes it reports the schema and the number of records read. Press Cancel to stop a model that is taking too long.
3. Drag in the 3D view to orbit and scroll to zoom. Press Fit model to reframe the whole building. Click an element to highlight it and read its attributes, property sets, quantities and type properties in the Selected element panel beside the canvas; press Isolate selected element to hide everything else.
4. Use Section planes to cut the model: tick X, Elevation or Y and drag the slider. The readout shows the cut distance from the model's minimum on that axis in the selected unit system. Press Measure, then click two points on the model to read the distance between them; Clear measurement removes the markers.
5. Switch Colour by to Class or Storey to tint every element and show a legend with counts. Press Save view to keep up to five camera positions in this browser, click a view name to return to it, and use its delete button to drop it.
6. Use the search box and the IFC class menu below the viewer to find elements by name, GlobalId, express ID, storey or property value. Click an express ID such as #37 to select that element in the model and show its full record.
7. Expand Project units to confirm the length, area and volume units before reading any values, then download the list with Export filtered CSV.

Worked example

Load the bundled two-wall IFC4 sample to explore two elements and their dimensions.

What is an IFC file?

IFC (Industry Foundation Classes) is an open, vendor-neutral data model for describing buildings and infrastructure. It is developed by buildingSMART International and published as the international standard ISO 16739. A native Revit (.rvt) or Archicad (.pln) file can only be opened by its own software, while an IFC file can be written and read by most BIM applications. That is why IFC is the usual format for sharing models between architects, engineers, contractors and owners.

An .ifc file is plain text in the STEP format (ISO 10303-21). Every line is a numbered record such as #37=IFCWALL(...), and records point to one another by number. A wall record points to its placement and its geometry; separate relationship records connect it to a storey, to property sets and to a type. The viewer follows those links to rebuild the model you see.

Models are organized as a spatial hierarchy. One IfcProject contains one or more sites, a site contains buildings, a building contains storeys, and physical elements such as walls, slabs, doors and windows are contained in a storey. That is why the class menu lists IFCSITE and IFCBUILDINGSTOREY alongside IFCWALL and IFCDOOR.

Section planes, measuring, colour modes and saved views

Section planes cut the model along the X, Y or elevation axis. Tick an axis, then drag its slider; the readout shows how far the cut sits from the model's minimum on that axis, in the selected unit system. Clipped surfaces are hidden rather than capped, so you look into the model as through a cut-away, and clicking still selects the visible element behind the cursor.

Measure reports the straight-line distance between two clicked points on the mesh surfaces, converted from the model's metre coordinates to metres or feet with the unit toggle. Because points snap to the triangulated geometry, not to grids or reference planes, treat the result as a check rather than a construction dimension.

Colour by class or storey tints every mesh from a neutral ramp, with the coral accent on the largest group, and lists each group with its element count in a legend. Storey names come from the model's spatial containment; elements with no containing storey are grouped as No storey.

Save view stores the camera position and target as a named view, up to five, in this browser only. Views persist between visits but belong to the model you saved them from: restoring a view on a different model simply points the camera at the same coordinates.

Which IFC versions can this viewer open?

Open an .ifc file in a text editor and look for the FILE_SCHEMA line near the top to see which version you have. IFC4 files produced under later addenda still declare IFC4 and open normally.

What the viewer shows, and what it leaves out

The viewer draws triangulated geometry with the colors stored in the model, and keeps each mesh linked to its IFC express ID, so clicking a surface selects the element behind it. The selected element is highlighted in orange. Isolate hides every other mesh, which is useful for checking one beam or door inside a dense model.

It is a model reader, not an authoring or coordination tool. Section planes and the two-point measure tool are inspection aids: there are no markups, clash checks or model edits, and measured distances follow the triangulated geometry rather than the parametric model. Geometry that the parser cannot convert is left out, and if nothing renderable is produced a warning appears under Model findings. The camera centers the model on screen for display only; the file's coordinates are not changed.

Every entity with a GlobalId appears in the table, including records with no geometry of their own such as property sets and relationships. Filtering by class is the fastest way to reach physical elements.

Worked example: checking a two-wall model

Press the IFC2X3 sample link. The status line reports IFC2X3 and 48 records read locally. Set the class menu to IFCWALL and two walls remain: #37 Sample wall A and #47 Sample wall B. Wall A is a 4 m × 0.2 m extrusion 3 m high (13 ft 1½ in long, 7⅞ in thick, 9 ft 10⅛ in high), and wall B runs at right angles to it.

Click #37. It turns orange in the 3D view and its record appears below the table, including Pset_WallCommon.IsExternal and Qto_WallBaseQuantities.Length with a value of 4. Expand Project units and you will see the length unit is the metre, so that value means 4 m. Click #47 and the Length quantity is missing, because the model never stored one for that wall. The viewer does not measure geometry to fill the gap.

Opening large IFC models in a browser

A browser viewer is limited by the memory available to one tab. This tool accepts files up to 50 MB and stops if a model has more than one million STEP records or would produce more than 200 MB (or 100,000 parts) of geometry. Those are guardrails, not a promise: a dense 40 MB model with lots of curved or detailed geometry can still exhaust memory on a laptop, tablet or phone.

If a model is too heavy, ask for a lighter export: one discipline or one building at a time, fewer storeys, or an IFC4 Reference View export, which is intended for viewing and coordination. Leaving out furniture, fixtures and other highly detailed families also helps. If you received an .ifczip, extract the .ifc with any ZIP utility first; the 50 MB limit applies to the extracted .ifc.

Who it is for and when to use it

Method, formulas & assumptions

web-ifc parses the model in a dedicated browser worker. Three.js renders supported geometry on your device. Select an element from the model or table.

Parser: web-ifc 0.0.77. Library notices.

Common mistakes to avoid

• Trying to open a native .rvt, .pln or .skp file. Export IFC from the authoring tool first.
• Opening an IFC4X3 file for a road, rail or bridge project. The viewer reads IFC2X3 and IFC4 only and will report the schema as unsupported.
• Reading dimensions without checking Project units. A model in millimetres and one in feet look identical in the 3D view.
• Assuming an element was never modeled because it is not visible. Unsupported geometry can be omitted, so check the table or the authoring model before raising an issue.
• Treating the on-screen position as survey position. The viewer centers the model for display and does not show site coordinates.
• Closing the tab before downloading an export. Nothing is saved, and the model is discarded when you leave the page.

Scope & limits

IFC2X3 and IFC4 STEP files, up to 50 MB per file. Tested on the included small IFC2X3/IFC4 fixtures; complex models can exceed device memory. Unsupported geometry may be omitted.

Frequently asked questions

Further reading

• All bim & files tools
• All free architecture & construction tools
• Harth resource library

In this category

• IFC property inspector
• IFC file health checker
• IFC merge