How to measure a room for a 3D room build

A 3D room is only useful if it's true to size. A sofa that looks right in a model that's 5% too wide will still arrive too big for the wall. So before anything else, the room itself has to be measured, and measured in a way that can be checked.

This guide covers what to measure and send for a room build, why a floor plan alone isn't enough, and how the measurements are used. It's written for a studio collecting details from a client, or for a client measuring their own room.

What you need

A tape measure, ideally 5 m (16 ft) or longer.
A phone for photos and a short video.
The floor plan, if you have one: a PDF from the builder, a listing plan, or a clear photo of a printed plan.
A second person helps with long walls, but isn't essential.

Step 1: Start with the floor plan

The floor plan gives the room's shape: where the walls turn, where the doors and windows are, and how rooms connect. It's the starting point for the 3D room.

But plans are drawings, not measurements of your room. Listing plans are often simplified, and builder plans show what was designed, not always what was built. That's why every plan gets checked with a tape.

Step 2: Take four tape measurements per room

For each room, measure:

One long wall, from corner to corner, along the floor.
One short wall, the same way.
The diagonal, from one corner to the opposite corner. This is the measurement people skip, and it's the one that catches rooms that aren't quite square.
The ceiling height, from floor to ceiling, away from any bulkhead.

Measure along the floor where the wall meets it, and keep the tape straight and clear of furniture. Write each number down with its unit, and note which wall it is (for example, "window wall" or "wall with the door").

This is the tape check. Four numbers take a few minutes, and they're what make the 3D room trustworthy.

Step 3: Measure doors and windows

For every door and window in the room, note:

the width of the opening, inside the frame;
which wall it's on, and roughly how far from a corner;
if you can, the height of each window sill from the floor.

Doors matter twice: once for the room's layout, and again for the delivery route, since every piece has to come through one.

Step 4: Photograph each wall

Stand in the middle of the room and take one photo of each wall, straight on, with the corners visible. Then take a slow video, about 30 seconds, turning around the whole room.

Photos show what numbers can't: built-ins, radiators, outlets, the floor and wall colours, and any big furniture that's staying. Existing pieces matter, because a new sofa has to work with the chair that's already there.

Step 5: Add the pieces

Send the store links for the pieces being proposed. Each piece is sized to the width, depth and height on its listing (W×D×H). If a listing is missing a size, it's typed in from the store's page or asked for, never guessed.

How the measurements are used

At Good Here, we build the room from the plan and the measurements you send. Before we build, we check that the numbers agree with each other and with the plan, and we flag any gaps. The room is as accurate as what you give us, which is why the four measurements matter.

Every room is built to its true dimensions, so furniture and layouts fit the way they will in real life. We're adding finer details next. Doors, windows and built-ins go where they really are. You don't need to learn how to build it.

The pieces go in at their listed sizes. Our 3D models are AI-powered and approved by a person. A piece that can't look like itself shows as a plain box at its true size, so the room stays honest about what's known.

What about scanning a room?

Some phones, such as recent Pro iPhones, have a laser sensor that can scan a room in a few minutes (LiDAR scan). A scan is a fast way to capture walls, doors and the big furniture. But scans aren't exact, so treat a scan as a draft until a tape measure agrees with it. If you send a scan, send the four measurements too.

A quick checklist

Floor plan (PDF or photo)
Per room: one long wall, one short wall, the diagonal, the ceiling height
Door and window widths (and window sill heights, if you can)
One photo of each wall, plus a 30-second video
Store links for every piece being proposed

That's everything needed to see a room true to size before anything is ordered. You can read more about how a room build works on our About page.

Questions about a project? Talk to us at hello@goodherestudio.com.