How do you switch floors in a 3D walkthrough of a home?
A 3D model of a multi-storey home is hard to show as one continuous space — the stairs connect two floors that are rarely scanned or drawn as one. Most apps solve it with a teleport point instead of a real staircase you can walk up.
Short answer: Most 3D walkthroughs in home apps switch floors at a fixed point — a portal, a marker, or a staircase model you walk into or tap — rather than letting you climb a real staircase step by step. The reason is technical: each floor is usually scanned or drawn separately, and the two floors are not connected as geometry, only as data. Whether the real staircase makes it into the scan depends entirely on the app, and on whether the staircase was scanned at all.
Why is switching floors hard in a 3D model?
A home with several storeys is almost always measured one floor at a time. That holds whether you scan with the phone's camera or draw it on paper afterwards. The ground floor is one continuous surface, the first floor is another — and the two are connected in only one place: at the staircase.
The problem is that the staircase is the hardest building element to capture accurately. It has sloped steps, a landing, often a railing full of gaps, and it stretches from one floor level to another. Most measuring tools are built to recognise vertical walls and horizontal floors — a staircase is neither. So it either gets heavily simplified, or it never becomes part of the geometry the model builds on at all.
The consequence: the app can easily show you two handsome, measured floors on their own. What it struggles with is stitching them into one model you can walk through without a break.
The three ways apps solve the floor switch
- Teleport point or portal. You walk to a specific spot — typically where the staircase stands, or in the middle of whichever room has the most connections to the rest of the home — and a tap or a pass-through moves you straight to the other floor. No steps, no gap. This is the most common solution because it does not require an accurate staircase model.
- Doll's-house view with a floor picker. Known from several 3D property scanners: the whole home is shown from outside and above, sliced into layers, and you click to open the floor you want to see. It is not a walkthrough in the classic sense, but a fast overview.
- A real, walkable staircase. Some apps build a simplified staircase model from the measured number of steps and the floor height, so you genuinely walk up it. It looks the most natural, but it requires the app to know the floor height precisely and to make a fixed assumption about step height — it is rarely a faithful copy of the real staircase.
None of the three is wrong. They answer different questions: overview, speed, or experience.
Does the staircase make it into the scan?
Only partly, and that holds for pretty much every measuring app that uses the phone's camera or LiDAR. The staircase's geometry — sloped steps, an open railing, a landing that turns — is exactly the kind of shape measuring algorithms are worst at, because they are trained to find flat walls and right angles.
In practice that means: the stair room is usually scanned as an ordinary room with a certain height, but the steps and railing themselves rarely come along as accurate, measured geometry. That is not a flaw in any one app — it is a limit on what room recognition is built to solve. If the staircase needs to be documented precisely, a few photos or a video are often more reliable than a 3D scan.
How does the app know where the portal should go?
When an app uses a teleport point instead of a real staircase, it still has to place the point somewhere that makes sense. The most useful rule is to put it in whichever room on each floor has the most connections to the rest of the home — typically a hallway, an entrance, or the landing, because that is where people actually pass through in real life. If the staircase's exact position is known from the scan, the portal can instead be placed right there, so the floor switch happens where you would expect it.
Basement, ground floor and first floor — do they connect in one model?
Yes, as data — but not necessarily as one continuous geometric body. Most apps store each floor as its own set of rooms and walls, with a shared floor height used to stack them correctly on top of each other when the whole house is shown from outside. The basement sits below ground level, the ground floor at ground level, the first floor above. That gives a correct outer view of the house, even though from inside you experience each floor as its own model, connected via the floor switch.
What you can do yourself for a better result
- Scan or draw each floor separately, from the same starting point. Most apps ask for this — it makes it easier to stack the floors correctly afterwards.
- Capture the stair room at its full height, even when the steps themselves are not accurate. The height is often used to work out the floor height.
- Note the number of steps and the step height yourself, if the staircase needs to be used for something concrete, such as ordering a new railing or a renovation. It is a measurement you will take faster with a tape measure than trust from a scan.
What HouseSense does
HouseSense shows a multi-storey home in a 3D walkthrough with a floor switch that looks like a floating portal: walk into it and you move to the next floor — above ground on the first floor, into the ground in the basement. By default the portal sits in the floor's most connected room, but it moves to the home's real staircase if it has been scanned and recognised as a staircase. The steps themselves are not part of the measured geometry — that is the same limit that applies to every measuring app, not just this one.
Should a professional draw the staircase instead?
If the staircase is to be rebuilt, moved, or included in a building application, a measuring app is not the right tool. Staircases are subject to requirements on rise-to-run ratio, railing height and headroom, which a professional or a design office measures and draws according to the rules that apply — not something a phone scan can settle. Use the app's model for an overview and to show where the staircase sits within the home as a whole. Use a professional for anything that gets built.