3D virtual tour glossary

The words that keep coming up in a 3D virtual tour, defined in one sentence each: equirectangular panorama, viewpoint, dollhouse view, point cloud, photogrammetry, depth map, absolute scale.

Updated 2026-08-17

Capture

Equirectangular panorama: An equirectangular panorama is a rectangular image twice as wide as it is tall, holding the entire sphere visible from one point: 360° horizontally and 180° vertically. It is the input format of every 3D virtual tour; a 360 camera produces one directly, and it is recognisable by its characteristic distortion, with ceilings and floors stretched into bands.
2:1 ratio: The 2:1 ratio is the mandatory proportion of an equirectangular panorama: its width is exactly twice its height, for example 8192 × 4096 pixels. An image that does not respect it is not a complete sphere and cannot be projected correctly.
Viewpoint: A viewpoint is a position from which a 360° capture was taken, and from which the visitor can look around. A virtual tour is a set of viewpoints linked together; it is also the billing unit. Visites-virtuelles platforms call them sweeps.
Overlap: Overlap is the share of the scene that two neighbouring viewpoints see in common. It is what allows their relative positions to be rebuilt: with no shared detail, nothing ties two captures together and one of them will not find its place. It is the main constraint of a successful shoot — see how to create a 360° virtual tour.

Reconstruction

Photogrammetry: Photogrammetry is the technique that derives three-dimensional positions and shapes from several photographs of the same scene, by recognising the same details from one image to the next. It makes it possible to recover where each panorama was taken when no position data comes with the photos.
Depth map: A depth map is an image giving, for every pixel of the panorama, the distance between the camera and whatever that pixel shows. It is what turns a flat spherical photo into a traversable volume: without depth you turn on the spot, with it you walk. It is either measured by the scanner or estimated by an artificial-intelligence model.
Point cloud: A point cloud is a set of three-dimensional points, each with its position, recorded by a distance sensor. It is the measured data of a scan: it describes the real geometry of the place and allows accurate measurements, where depth estimated from photographs remains an approximation.
Mesh: A mesh is the continuous surface rebuilt from a point cloud or a depth map, onto which the colours of the photographs are then applied. It is what gives the overview of a tour the look of a solid object rather than of scattered points.
Absolute scale and relative scale: Absolute scale is the correspondence between the tour and the real world: it lets you say a wall measures 3.40 m. Relative scale only gives correct proportions between objects, with no real size. 360 photos alone provide relative scale only — nothing in images says whether a room is three metres across or six. A Visites-virtuelles backup or link brings absolute scale.

The tour

3D virtual tour: A 3D virtual tour is a navigable reconstruction of a real place, in which you move from viewpoint to viewpoint while looking around, as if you were there. It differs from a plain 360 panorama by the movement, and from a video by the fact that the visitor chooses the path.
Dollhouse view: The dollhouse view is the representation of the whole property cut away and seen from above, like a model with the roof removed. It is used to grasp the layout of the rooms at a glance before entering the tour, and to choose where to go.
Floor plan: The floor plan is the flat top-down view of the property, with the location of every viewpoint. It works as a map: clicking on it moves the visitor. It is produced automatically from the reconstructed geometry.
Self-hosted (standalone) tour: A self-hosted tour is a tour delivered as files that depend on no outside service: no vendor server, no CDN, no remote font, no tracker. It works offline, can be hosted anywhere and keeps existing without a subscription — see hosting your virtual tour.

Visites-virtuelles data

Visites-virtuelles backup (.zip): The Visites-virtuelles backup is the archive produced by the capture app, containing the raw scan data: the captures of every viewpoint and the measured point clouds. It is the most complete source, the only one carrying the original measured geometry — how to recognise it: exporting a Visites-virtuelles tour.
Visites-virtuelles share link: The share link is the public address of a published Visites-virtuelles tour, of the form my.matterport.com/show/?m=…. It gives access to the images and viewpoint positions as the player shows them, but not to the measured point clouds.
Hybrid mode: Hybrid mode means supplying both the share link and the backup of the same tour. It is the only one combining the measured geometry of the backup with the original colour rendering of the player, and it is the one that gives the best result.

Seeing these ideas at work

The same properties produced in all four formats: the fastest way to understand what each term on this page actually changes.

Hybrid Backup Link 360° only

Frequently asked questions

What is the difference between a 360 panorama and a 3D virtual tour?

A 360 panorama is a single image: you turn on the spot, with no way to move. A 3D virtual tour links several viewpoints and adds depth, which lets you walk from one place to another, see the property cut away and measure.

What is a dollhouse view?

It is the view of the whole property cut away and seen from above, like a model without a roof. It shows the layout of the rooms at a glance and lets you pick where to enter the tour.

Why is 360 capture said to have relative scale?

Because photographs alone contain no distance measurement: they give correct proportions, but nothing indicates whether a room is three metres across or six. A source carrying measurement — a point cloud or recorded positions — is needed for absolute scale.