On your desk is a floor plan carrying a square-metre figure that came out of a device. What did the device measure, how precisely, and what may you use the number for?
Three different things are called a “Matterport floor plan”, and they differ considerably:
This is the heart of it, and it is not an accuracy problem but a difference in definition. Even a perfectly accurate measurement would not produce an SIA area.
Matterport offers only the RICS and ANSI area standards. Asked about country-specific requirements, its documentation answers verbatim: “We currently do not support country-specific requirements.” No SIA 416 option exists — so there is not even an attempt at conformity.
What matters is where the measuring line sits. The RICS standard measures to the inside face of external walls but includes internal walls. SIA 416, by contrast, defines two floor areas: one including all construction areas and one excluding them entirely. The scan figure sits between the two and matches neither.
There is no conversion factor, because the difference depends on the individual internal wall layout. A figure from the scan can therefore be presented neither as a net floor area nor as a gross floor area under SIA 416.
A scanner captures visible surfaces. Everything else is drawn, interpolated or assumed — and that is exactly where deviations arise:
| Case | What happens |
|---|---|
| Wall thicknesses | Not measured but drawn. Derivable between two scanned rooms — at an external wall, or towards an unscanned neighbour, not at all. Matterport offers a flat 15.24 cm assumption for the whole perimeter instead. A flat assumption is not a measurement. |
| Sloping ceilings | The countable area is derived from the reconstructed ceiling model — precisely where the scan is weakest, because the camera sits at tripod height and meets the slope at a shallow angle. Small errors in the pitch shift the boundary line disproportionately. Attic floors are the most error-prone case. |
| Built-in wardrobes | Only the front is captured, never the interior. Whether the depth counts towards the area is a drawing decision, not a measurement. |
| Furnished rooms | Every stretch of wall hidden by furniture is interpolated — the wall line behind a sofa or cupboard is calculated, not seen. |
| Unscanned rooms | Cellars, attics and plant rooms are usually left out of a marketing scan on purpose. They are then missing from every derived total. |
| Glass and mirrors | Reflective and transparent surfaces return unreliable measurement points. |
Matterport publishes accuracy figures for single scans under laboratory conditions — for instance ±20 mm over 10 m for the Pro3 camera — and qualifies them in the same passage: those figures do not imply that every measurement in a finished model will meet them.
Our own figure and what it is based on. We state 2 to 3 % on a wall-to-wall distance, measured inside the tour (as of 2026). We work with a 360° camera; Matterport computes the depth from the images using AI. For this capture method, Matterport states an average deviation within 4 to 5 %; in a comparison test, most wall-to-wall measurements were within 2 to 3 %. Our own check measurement came out at 3 to 5 cm over 2.5 m, roughly 1 to 2 %. Individual measurements can still deviate more. These are explicitly not exact dimensional values. If we switch to a camera with an active depth sensor, we will revise the figure.
For comparison: the Swiss market offers phrasings such as “extremely accurate” or “approx. 98 %” — both without a reference quantity, a sample or a date. A percentage without a stated basis cannot be checked.
| Suitable for | Not suitable for |
|---|---|
| Listing and marketing Viewing preparation Furniture and moving planning Preparing a tradesperson's survey Documenting the fit-out condition Drafting a management plan |
Area figures in a tenancy or purchase agreement Service-charge and area allocation keys Value quotas in condominium ownership Building applications, permissible floor area Anything resting on the official cadastral survey |
For the right-hand column we supply a dimensioned PDF plan at 1:100 on request. That too does not replace the official cadastral survey — it is the basis a professionally competent body can build on.
Switzerland has no statutory definition of living area — no equivalent to the German Wohnflächenverordnung. Nor is there a professional monopoly: an area becomes binding not through the title of whoever measured it, but through the document it appears in.
Whoever states an area is held to it — and the other party need not re-measure. In 4A_108/2019 (judgment of 22 January 2020) the Federal Supreme Court held that a deviation of roughly 4 % is in principle not an objectively material error. In that specific case it nevertheless found a fundamental error, because the landlord had written exact areas into the contracts and set the rent accordingly.
Hence the practical rule we work by: a scan figure never replaces the contractual area. That is why we supply it as a marketing basis — and label it as one.
To copy into a listing or plan legend if you reuse our plans:
No. Matterport offers only the RICS and ANSI area standards, and on country-specific requirements its documentation states verbatim: “We currently do not support country-specific requirements.” The RICS standard measures to the inside face of external walls but includes internal walls. SIA 416, by contrast, defines one floor area that includes all construction areas and a net floor area that excludes them entirely. The scan figure sits between the two and matches neither. This is not an accuracy problem but a difference in definition: even a perfectly accurate measurement would not produce an SIA area.
RoomView360 states 2 to 3 percent on a wall-to-wall distance measured inside the tour (as of 2026). The figure is based on our own check measurement and a Matterport comparison test in which most wall-to-wall measurements were within 2 to 3 %. For captures with a 360° camera, Matterport states an average of 4 to 5 %, so individual measurements can deviate more. These are explicitly not exact dimensional values.
As a marketing basis: the listing, viewing preparation, furniture and moving planning, preparing a tradesperson's survey, and documenting the fit-out condition. It is not suitable for contractual area figures in a tenancy or purchase agreement, for service-charge or area allocation keys, for value quotas in condominium ownership, for building applications and permissible floor area, or for anything that rests on the official cadastral survey.
Because a scanner only captures visible surfaces. Between two scanned rooms a wall thickness can be derived; at an external wall, or towards a room that was not scanned, it cannot be determined from a one-sided scan at all. Matterport offers a flat assumption of 15.24 cm for the entire building perimeter instead. A flat assumption is not a measurement — which is why no construction area or gross floor area can be derived from a scan floor plan.
There is no statutory definition of living area in Switzerland and no professional monopoly. An area becomes binding not through the title of whoever measured it, but through the document it appears in — the tenancy or purchase agreement. Whoever states an area is held to it. In 4A_108/2019 the Federal Supreme Court held that a deviation of roughly 4 percent is in principle not material, yet still found a fundamental error in that case, because the landlord had stated exact areas and set the rent accordingly.
Whenever the area feeds into a document someone will be held to legally: a tenancy agreement, a purchase contract, a building application, condominium ownership, a service-charge key. RoomView360 supplies a dimensioned PDF plan at 1:100 as an add-on for that. For legally binding areas, a professionally competent body should also be involved — a chartered surveyor, an architect or a property valuer.
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