How an iPhone sees a room

Pásek isn't built on magic — it's built on a sensor that newer iPhones and iPads carry right on their back. It's called LiDAR and it works like a bat: it fires beams of light and measures how long they take to return. From that it knows the distance to every surface in the room, ten times a second.

From points to a plan

Raw LiDAR data is a point cloud — pretty to look at, useless on its own. The key is the software that makes sense of it. Apple ships that as RoomPlan, and Pásek calls it directly: as you walk through the room, RoomPlan recognises in real time what's a wall, a window, a door, and where a piece of furniture stands.

The result isn't a photo or a point cloud. It's a parametric model: "a wall 4.2 metres long", "a window 90 centimetres wide". You can compute with a model like that — work out areas, draw a floor plan, pull dimensions.

Why this way

• Speed. An ordinary room takes one or two minutes. No tripods, no markers taped to the walls.
• Clarity. A parametric model becomes a clean floor plan, not a mess of triangles.
• Honesty. A scan is an excellent estimate, but it's not a surveyor's laser. That's why Pásek declares, for every measurement, where it came from and what its tolerance is — there's a separate article on that.

What you need

LiDAR is in iPhone Pro models (12 Pro and newer) and iPad Pro. Without it there's no scan — but Pásek plans for that: you can enter dimensions by hand from a tape measure and assemble the model yourself. LiDAR is an accelerator, not a requirement.

Pásek is an orientation tool, not a geodetic survey. For official use or a boundary survey you need a licensed surveyor.

Next time we'll look at why, in an old farmhouse, we deliberately don't straighten walls to right angles — even though it would look nicer.